E.on customers have been hit by a billing glitch that means their direct debit energy bill payments will be taken later than expected this month.
It means households will need to make sure they have cash in their account so they can cover the payment when it comes out.
The technical issue affects potentially thousands of customers with E.on Next and Sainsbury’s Energy, both of which are owned by E.on.
It relates to payments that were due to be taken on March 1 but will now leave accounts on March 15 instead - two weeks later.
E.on customers who are affected by the blunder should have been contacted by the energy supplier, explaining that the bill will come out at the later date.
If you manually paid your bill after your direct debit failed, then you shouldn’t have another payment taken by E.on on March 15 as you would've already paid your bill.
But if another transaction does go out by mistake, you should contact E.on - you can find ways to speak to its customer service team on its website.
E.on says April payments should leave accounts on the correct dates.
Are you worried about paying your energy bill? Let us know: mirror.money.saving@mirror.co.uk
The energy giant hasn’t said exactly how many people have been hit by the blunder but said it is a "relatively small number".
MoneySavingExpert also said it has heard from dozens of people on social media and the MSE Forum about the delay.
E.on has more than three million UK customers.
A spokesperson for E.on said: “This issue is being resolved and we are contacting affected customers to apologise and inform them that their payment will now be taken on or around 15 March.
“This will not affect payments going forward.”
The billing error from E.on comes as households brace for rising energy bills from next month.
Regulator Ofgem has confirmed it is increasing its price cap by £693 from £1,277 to £1,971 from April 1 - a rise of 54%.
Prepayment customers will be worse hit, with a jump of £708 from £1,309 to £2,017.
The energy price cap sets a limit on the rates a supplier can charge for each unit of gas and electricity you use and is currently reviewed twice a year.
Rising energy bills mean the usual advice of switching suppliers has been turned on its head - with there being no fixed-rate energy deals right now that beat the price cap.
The only exception is for some existing customers, who may find their energy provider offers them a deal that matches the price cap.
For example, earlier this month, a cheap fixed-rate deal by E.on was pulled just hours after it was flagged by Martin Lewis.
The MoneySavingExpert founder had flagged the E.on Next Online V11 one-year fix to his 1.3million followers on Twitter, which was set at the same rate as the April 2022 price cap.
E.on customers who pay by direct debit, and are currently on the price cap, were being offered the deal by post and through the E.on website.