Martin Lewis has apologised for his advice about non-smart prepayment meters after energy companies backtracked on their earlier confirmation.
The MoneySavingExpert founder previously said customers who topped up their prepayment meters before the price cap rise on April 1 would be able to save on gas and electricity – because they would pay the cheaper rate.
He told worried energy customers if they topped up a non-smart prepayment meter before the April 1 price cap rise they would be charged the cheaper rate.
Mr Lewis said MoneySavingExpert received written confirmation of the prepayment meter rates from all major firms except Scottish Power.
But he has now apologised through his MoneySavingExpert website after it emerged the bulk-buying hack won’t work on all suppliers.
He reiterated his concerns when speaking as a witness to the Business, Energy and Industrial Committee about his fears surrounding rising energy prices.
He told the committee the energy hack "was of course the advice and guidance we've been giving".
He added MoneySavingExpert "had it confirmed by Ofgem and all companies apart from Scottish Power which said it would have a debt on top."
The consumer champion also warned about "worrying issues" of energy companies increasing customers' direct debits disproportionately to the price cap increase.
He told the committee: "There is no reason to double someone's direct debit when they're in credit and the price cap is going up 54%.
"That's not mathematically sound and it's a breach of licence conditions.
"I have been very concerned that a number of companies are doing it to improve their cash-flow situation at the expense of their customers, and I would like to see the regulator crack down on that quite substantially.
"It's important to remember that there is no competition in the market any more. This is not a market - no one can switch."
Although the price hike is set to affect many households, Mr Lewis said a lot of people won't have to the tools to be able to handle the situation.
He said Ofgem is under resourced to deal with the number of issues with the market.
He said: "There's so much going on in the energy market and OfGem is under resourced to deal with the number of companies gone bust and what's happening in the energy market. The amount of playing fast and loose that seems to be going on is huge right now."
With energy bills due to rise by an average of 54% on Friday, April 1, millions of households are being urged to take gas and electricity meter readings the day before.
The aim is to ensure you get the current, cheaper rates for all the energy you use right up until close of play on Thursday. Otherwise your supplier might charge some of it at the new higher unit prices.
Gareth Kloet, the energy spokesperson at the comparison site GoCompare, said: “We would urge all bill payers to take both gas and electricity meter readings on 31 March and make sure you submit these to your supplier.”