An Oxfordshire man says he was astounded after his energy supplier told him he owed nearly £30,000 on his latest bill.
Patrick Collins, from Henley, had his supply taken over by Shell Energy after his previous supplier went bust - when Russia's invasion of Ukraine caused the cost of gas to skyrocket.
His first bill with Shell showed that he owed an eye-watering £29,681.53 for his gas and electric use.
The bill claims that Mr Collins used £9,781.87 worth of gas in just a matter of weeks.
Mr Collins says the problem left him struggling to sleep, after numerous attempts to resolve the problem with the energy company failed.
He said: "I've found that it has actually kept me awake at night, thinking, am I going to have to pay this bill? Who is going to believe me?"
Patrick says he's spent ten days on the phone to Shell Energy, and sent 65 emails and numerous photos of his meter.
It turned out that the high charge to Mr Collins' account was the result of an incorrect meter number.
A spokesperson from Shell Energy said: "We're really sorry for the mistake with Mr Collins' bill.
"We have apologised and explained the error, which was the fault of an incorrect meter number.
"We're correcting the error and he'll have an up to date bill very shortly."
Mr Collins added: "If I was a pensioner or something like that, it would have been very bad for my health getting a bill like that.
"I want something in place so customers can actually reach help more easily, rather than having to go through the frustrating time that I have."