Some customers have received energy bills of up to £80,000 after OVO took over SSE.
One of them, Andy Liggins saw on his smart meter that he was paying £79,580.45 per hour for gas – he wrote on Twitter: “I know the rates are going up but….”
One woman was told she owed £44,800 for two months’ supply of energy for her one-bedroom flat.
She told the Guardian: “I had been asked to send photos of my meters in August as OVO believed there was an issue.
“I did so and my account went from £600 in credit to £19,000 in debt. Despite OVO assuring me this was a mistake, the debt rose to over £44,000 in September.”
Another customer’s monthly direct debits rose from £418 to £1,989 after OVO calculated that he used £23,330 worth of energy throughout July and August.
Alistair Strain’s projected energy bill for next year was £29,000.
An OVO spokesperson told ELN: “We are very sorry to Professor Strain for the experience he has had since his account moved to OVO.
“We have refunded the amount incorrectly taken to his bank account and offered a goodwill gesture. We have processed millions of successful migrations to date, but we are aware of a small handful of customers receiving large projections. To resolve this, our teams have set up an extra control to check for large bills to make sure we identify them, and fix them before they’re sent to customers.”