If you were contacted by a number that you didn’t recognise, it could be about something important. However, it is certainly also possible that it is a telemarketer who would like to sell something to you. Not every call under this category is suspicious.

Advice: You should be wary, but you can pick up the call. Take note of whether the caller introduces themselves with their name and that of the company as well as their reason for calling. If it turns out to be a nuisance call you can simply end the conversation and tell the caller that you are not interested.

A trustworthy number could for example be an acquaintance or a business partner whose number you don’t have saved in your contacts. These types of call are often made by your own insurance provider or bank, wanting to arrange an appointment, or by a customer service department wanting to tell you about a new offer or a change in your contract. Trustworthy numbers, in short, will not annoy or pester you.

Advice: You can answer these calls without a second thought if you know the caller or are sure who you are speaking to. However, if you are unsure if the caller or the company is trustworthy, you should search for the number on Telspy to get further information or to warn other users about the caller.

Have you received a call from a sweepstake or competition company? Competitions are very popular and there are opportunities everywhere to take part. However, they are not always trustworthy and you should be especially wary of calls of this type. As a rule, winners of competitions are not contacted by telephone. During these kinds of calls, people are regularly told that they have recently taken part in an online competition. In order to receive their winnings, they must first subscribe to a magazine or pay a fee in advance of the payment. Through this method, scammers try to get hold of your bank details.

Advice: To claim your winnings, you never have to pay a fee. If you actually had taken part in a competition, ask for the details to be sent to you via email. If not, you should end the call.

Many firms can come under this category, for example internet portals, email service companies and telecom providers. The caller informs you that you have outstanding costs on your contract which you must pay as soon as possible. In reality in most cases there is no contractual basis for the demands.

Advice: If you receive a call from a debt collection company, you should be told precisely what the debt is for. This way you should easily be able to recognise if it is a fraudulent call. Whether a real debt collection agency or a fraud, you do not have to put up with disruptive or abusive calls. In this case you can report the calls to the police or Action Fraud.

Advertising calls can contain trustworthy offers. However, to receive such calls you should have previously agreed to them. Unsolicited marketing calls are unpleasant and a waste of time for most people and in many cases they are not permitted. If someone carries out marketing calls without any permission, then they are not allowed. Of course, it can happen that the caller introduces an interesting product, but you certainly shouldn’t make a purchase over the phone without informing yourself about the product or company beforehand.

Advice: If the marketing call is tempting, request for a written offer to be sent to you and do not hastily agree to any contract over the phone. Often, you are not aware of the terms and conditions or the company turns out to be different to what they claimed. It is also not easy to cancel such contracts. Online you can find many experience based reports about companies who advertise their products over the phone.

Have you been contacted by a polling company? Telephone surveys are a common way of carrying out market research and opinion polling. These calls are permitted even if they are not of interest to everyone. Usually the caller only asks a few short questions over the phone about topics such as politics and consumer habits.

Advice: If you no longer wish to be contacted by the polling agency, make sure that you express this on the phone. It has also often been reported that some supposed surveys about product habits turn into an agreement to a purchase. You should report these kinds of calls to the police.

This term refers to many different types of annoying calls such as cold calls, aggressive calls and silent calls. In most cases the person or company calls you many times from the same phone number. An example of this is the so called "Tech Support Scam", where the caller claims to be from a computer manufacturing company such as Microsoft in order to find out your personal details. By repeatedly calling, the fraudster attempts to persuade you to believe their story and share your details.

Advice: If a telephone number annoys you constantly you can simply block the number. You can also use certain apps to block callers. In order to prevent this possible fraud, you should search for further information about the number before revealing any of your details.

This type of call is not trustworthy. A scammer will use dubious methods to try to steal money from you. The company could pretend to be from a competition company, or to be selling subscriptions or office products such as coffee machines and printers. The caller, however, does not give you the full details about the products, nor about the contract involved. Suddenly, you may subsequently receive bills for purchases that you had not made.

There are other types of call which come under this category, for example the grandchild trick, where the caller pretends to be a family member in order to persuade you to give them your cash. Other examples are calls where the caller pretends to be a police officer, lawyer or a notary. Such callers take advantage of vulnerabilities and inform those on the other end of the line that they must transfer money to pay for a court case or in order to receive prize money.

Advice: Never arrange a contract over the phone and don’t hand over any sensitive information! As a rule, the authorities will never contact you by telephone – they would always send you information by post. Ask lots of questions to determine the identity of the caller. If in doubt, end the call straight away and inform the relevant authorities.

The term telemarketer refers to calls originating from call centres, where the caller attempts to sell their products or carry out surveys. Although this type of call is not usually dangerous, some callers do not behave in a trustworthy manner. Such callers try to pressure you into buying their products and services.

Advice: If you receive an unexpected call from a telemarketer, you can always send the company a written request to opt-out. Alternatively, you can report the number to the police or Action Fraud if you find it particularly disruptive.

Over the years, ping calls have been reported more and more regularly. Although we are warned about them by the media, these calls continue. Ping calls refer to a call that only rings once, meaning that there is no opportunity for you to realistically answer the phone. Such fraudsters hope that you will call the number back. In most cases these calls originate from abroad, meaning that you will incur high costs if you ring back. You may even be kept on hold in order for the scammer to generate the highest possible call costs.

Advice: Have you received a ping call? If it was an unrecognised number that originated from abroad it is advisable that you do not call back, especially if you do not know anyone who lives abroad. In this way you can avoid possible associated costs.