Imagine going to check your bank balance and finding you're overdrawn by £1.5 million.
That's what happened to Paul Livermore from Worthing.
He says there's no way he could have run up the debt, and his accounts should be in credit. His bank, Barclays, say they're investigating, but meanwhile Mr Livermore - a father-of-three - is struggling to pay essential bills.
It comes after mounting concern about the safety of online banking, and the crisis that TSB customers have been facing.
Watch the full report by Malcolm Shaw here:
Paul Livermore uses telephone banking to check his current account with Barclays. He normally expects it to be in credit.
But the figure he was given left him shocked and bewildered.
Mr Livermore checked his other two accounts with the bank, only to find they were overdrawn by similar amounts. A total of around £1.5 million.
The father-of-three immediately contacted the bank and went to his local branch. But he says he was given no explanation and was just referred to the bank's terms and conditions.
Paul Livermore's problems come as concern mounts about online banking. Customers of TSB have suffered five days of disruption after a new computer system stopped them accessing their money.
Nicky Morgan MP- Treasury Select Committee says online banking should be completely reliable to customers:
Mr Livermore has been unable to access his accounts for three weeks.
He hopes he'll be able to access his next month's pay, but has no idea what will happen to the £1.5 million black hole in his accounts with Barclays.