If you've been using Groupon to snap up some more affordable Christmas presents, you might want to check your bank account for fraudulent activity.

A number of users of the deals-grabbing service have seen hundreds of pounds stolen, as hackers snap up expensive goods using their accounts.

The first sign of unapproved activity popped up earlier this month, with Groupon account holders receiving confirmation emails for products they hadn't purchased.

A number of users of Groupon have seen hundreds of pounds stolen, as hackers snap up expensive goods using their accounts

SHOULD I WORRY ABOUT THE GROUPON HACK? Groupon itself hasn't been hacked, but it has confirmed some user accounts have been accessed by hacker using details obtained elsewhere. These users have seen multiple purchases made on their accounts without their permission. Some have reportedly lost up to £1,000 as a result. Many have criticised Groupon's lack of help solving the issue. You're advised to change your password if you're worried you could be targeted. Advertisement

Now, some users have reportedly been left up to £1,000 ($1240) out of pocket, and users around the workd are being advised to check their accounts for signs of unusual activity, according to an investigation by MoneySavingExpert.com.

Some of the hackers are buying high-ticket items including iPhones and iPads.

Although Groupon says it hasn't been hacked itself, the company has confirmed users in the UK have been compromised.

Hackers are using usernames and passwords acquired in attacks of other sites and services.

'I can confirm there has been no security breach to our website or mobile app,' a Groupon spokesperson told MailOnline.

'What we are seeing however is a very small number of customers who have had their account taken over by fraudsters.

'Fraudsters have a number of ways in which they can obtain your login details to a website including phishing e-mails, trojan attacks, spyware and malware.

'By using these methods, it's possible for fraudsters to get customer account information, log in and make purchases.'

Advising customers on what to do, they added: 'As with any major online retailer, we take fraud extremely seriously and have a dedicated team to investigate customer issues as soon as they are reported.

'If someone believes they've been a victim of a fraudulent attack, we investigate it and if confirmed - block the account immediately and refund the customer's money back to them.

Despite the firm's statement of intent, as well as losing out financially, Groupon's disgruntled users have been left infuriated by the company's seemingly poor customer service.

Many have taken to Twitter in order attack the company's lack of help and call for assistance.

The first sign of unapproved activity popped up earlier this month, with Groupon account holders receiving confirmation emails for products they hadn't purchased

'@Groupon_UK after you just allowing someone to hack my account and purchase £1000 of goods can you contact me to cancel my account,' user Ellie Coome Tweeted.

PASSWORD RE-USE ATTACKS Password re-use is one of the biggest concerns facing online accounts today, but this issue could be overcome by using unique password on each website, or using a password manager. Mark James, an IT security specialist at ESET, told MailOnline: 'Quite often we don't value all websites with the same level of security, duplicating passwords on what we assume is a low security website could enable hackers to get your details and try those on your very important logins like financial or shopping websites with success. 'It's very difficult to remember our details for every site we log in too, almost everything we do on the internet requires us to create an account and store more details on servers that we have no control over their level of security. 'The only thing we can control is the usefulness of the data we provide, keeping it unique or managed is the only way forward in today's digital world.' Advertisement

@Groupon_UK after you just allowing someone to hack my account and purchase £1000 of goods can you contact me to cancel my account — Ellie Coome (@Elles1990) December 4, 2016

Her comments were echoed by Sherelle Fiarweather who said: '@Groupon_UK my account hacked and a lot of money taken for a purchase I did not make. Your lines closed. Can you please reply to my email?'

@Groupon_UK my account hacked and a lot of money taken for a purchase I did not make. Your lines closed. Can you please reply to my email? — Sherelle Fairweather (@szm_fairweather) December 17, 2016

They're not alone either, one user told MoneySavingExpert: 'I immediately phoned Groupon – however the office was closed and reopened between 9am and 5pm Monday to Saturday. No more I could do.

'On Saturday morning I called Groupon at 9am only to hear the same message and be hung up on at the end of the message. I tried repeatedly throughout the day but no joy. I simultaneously phoned RBS and cancelled my bank debit card. The bank advisor confirmed he could see the transactions in my pending payments.

'I eventually got through to a Groupon customer advisor, who after many waffling excuses eventually told me that the best I could hope for was that they were reviewing the matter and someone would get back to me within ten days.'

But Jonathan Sander, VP of Product Strategy at Lieberman Software, told MailOnline that social media was stirring the issue.

He said: 'What we’re seeing with the Groupon security complaints is the triumph of social media noise over common sense.

'If Groupon users decided to do what every security expert on earth, and likely every other service the user interacts with has told them again and again NOT to do – use the same password for many websites and services – then how can the user expect anything but these terrible results?

'This problem comes from users’ not making good choices even when they know the potential consequences.

'The reason so many security professionals feel like their advice is like "eat right and exercise" is because, just like health advice, people only seem to follow security advice after something terrible shows them bad things can happen to them, too.'

MailOnline has contacted Groupon for comment and are waiting on a reply.