Gas and electricity supplier Extra Energy has apologised to some former customers after it sent out emails wrongly telling them they owed £100s.
The company says the error happened as the result of a "technical issue" and that it has now contacted all those affected and explained they do not owe cash.
If you received the email, and didn't owe money, Extra Energy has confirmed to us that your credit file won't be affected - but if you have questions, you can contact its customer care team on 0330 303 4774.
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What did customers say?
We received emails and saw social media posts from several disgruntled former Extra Energy customers.
One MoneySaver told us via email: "In December 2015, I switched from Extra Energy to a new supplier, to get a better deal. On 31 May 2018, I received an email stating that I owed them over £100, overdue from my latest bill."
"I was rather annoyed, and phoned them next day to ask what was going on. The customer payments lady explained that there was a systems error affecting numerous customers."
Another said: "Back in 2015 I was with Extra Energy. When I left in 2015 they owed me £299.07 which they paid into my bank account on 4 January 2016."Today I have received an email demanding payment of the £299.07. When I rang them I was told that there was a technical problem as lots of customers had been reporting the same error."
Extra Energy says it has now contacted affected customers
Extra Energy told us it had identified all those affected by the issue and has contacted them to apologise and confirm they do not owe money.
It also confirmed to us customers' credit files will not be affected by the issue.
If you think you've been wrongly told you owe money by Extra Energy, and haven't had a follow-up email saying that you do not owe money, contact Extra Energy on 0330 303 4774 or via email, on firstname.lastname@example.org.