Big six energy provider Npower has agreed to some of's calls to wipe ex-customers' bills after it came under fire for sending former users huge demands for cash months after they'd left the firm.

Last week we warned how we'd seen a raft of complaints on social media and on our forum about households who'd switched away from Npower thinking everything was done and dusted, only to receive shock bills months later due to Npower's own disgraceful failings (see the Npower's slapping ex-customers with huge bills MSE News story).  

Many faced 'back bills' demanding £100s, even though they'd had no reason to budget for such expenditure. Some bills even came over a year after they'd left the firm, while existing Npower customers also reported bills arriving late.

At the time, Npower wouldn't budge from its existing "back-billing" policy, where it only writes off charges when it is forced to by an industry code. The code says bills over 12 months old should be waived for customers who have experienced issues that are the company's fault.

But a few days ago, Npower said it'd had a rethink following a sustained campaign by MSE creator Martin Lewis berated the firm on BBC Radio 5 Live, saying: "It must do the decent thing – wipe or at least reduce bills to a manageable amount, set up an easy repayment plan, and ensure it puts no one into fuel poverty."

After discussions with Martin over what would be an acceptable solution, Npower says it will now be much more lenient with both former and existing customers. But there's still one element of contention...

So what's Npower going to do?

  • Ex-customers who left six months ago or more (since 1 December 2013)

What happens here depends on which of three categories you're in. All three of these solutions apply where the back bill relates to debt you didn't know about from an account you thought was done and dusted. You'll still have to pay any debt you knew about, and that you'd been billed for already.

1. If you haven't received a back bill, but it was going to send you one.

Quite simply, Npower will now wipe this bill, so you don't have to pay it.

It plans to write to affected ex-customers to tell them about this. But you should still ring Npower now to check you're definitely not going to be asked for this cash back.

2. If you received a back bill, which you haven't yet paid.

This is a contentious point. While it was originally hoped Npower would wipe these bills too, the firm's currently saying you'll still have to pay up. It says it'll do what it can to help ex-customers who feel they may struggle by extending the payment terms or helping those in hardship. is calling for Npower to reverse its decision, and to wipe these bills instead. Npower says it will go back and discuss this point, and we'll update this news story as soon as we hear anything.

Martin Lewis says: "It seems a rather ridiculous distinction to say that everyone who's had a bill in this scenario has to pay, but those not yet sent it won't.

"In other words, it's a random act of Npower's failing billing system that decides whether people need to pay or not. That's not fair. 

"I am strongly urging Npower to take that back to the discussion table. For those in this position, if you're in financial hardship I suggest you call it up and ask for the bill to be wiped.

"For everyone else, don't pay the bill right now, give Npower time in case it changes it's mind. We will update you here."

3. If you received a back bill, which you've since paid.

Unfortunately, Npower isn't going to automatically refund what you've already paid. But if paying the bill has caused you problems, you should call it.

Martin Lewis says: "While this is a little frustrating, Npower has agreed to look at these on a case-by-case basis.

"So if you're in this position, make a call and politely explain the issue. This is especially important if paying the bill has put you in financial hardship, as that may make it more lenient."

  • Existing customers who've received a bill six months or more late

You'll still have to pay it, but Npower now says you'll be treated sympathetically. If you need to, it says you should ring up and ask for it to set up a plan to help you pay at a pace you can afford.

Martin Lewis comments: "Npower has agreed to look at reducing the amount some customers in this situation owe. I've heard of cases where this has happened, so it's worth talking to it if this has impacted you."

  • Ex-customers who left less than six months ago and existing customers who received a bill less than six months late

If you got a bill in this time period, you'll still have to pay it. But Npower says it'll extend repayment periods and set up payment plans where it's asked to do so.

So if you're struggling and need longer to pay, get in touch with Npower now and ask it to extend your payment period.

Martin Lewis comments: "One of the points I pushed strongly for was that people in this position who have been put in severe financial hardship, should have their bills wiped, as it's unfair for those strictly budgeting.

"Npower has conceded that it will look at these on a case-by-case basis, so if you have provable hardship, especially if paying this additional amount pushes you further into trouble, then speak to Npower and politely explain the point."

What does Npower say?

Npower says: "In December, we apologised for customer service problems, in particular with late billing. We said clearly that we don't want anyone to suffer financially as a direct result of our billing system issues. Since then, we have been working hard to address these issues.

"In the light of our late billing problems, we agree with Martin Lewis that if someone left us over six months ago and hadn't heard from us since then, they'd expect that their account was closed.

"Therefore, if a customer left us before December 2013 and still hasn't received a final bill we won't ask for any more payment for the energy used, as long as there wasn't any previous debt that we had told them about.

"We'll be in touch with these people over the coming weeks. As always, if any of our customers have concerns or worries about paying their bills, please do talk to us and we'll see how we can help.

"Any customer having any genuine difficulty in paying a bill they have recently received should get in touch to discuss it. We will see what we can do to help. We have helped many people so far, for example by agreeing extended payment periods."

Npower 'hasn't gone far enough'

Martin Lewis says: "It's important to recognise that Npower has moved on this. Last week it was saying categorically that anyone who had a shock bill within a year of leaving would have to pay it full stop. Now, in some cases it is wiping bills, and in others, it's offering more favourable repayment terms. 

"But it hasn't gone far enough. After conversations earlier in the week I had hoped it would be wiping all shock bills over six months old, and after a frank exchange on Radio 5 Live a couple of hours ago, I hope it will reconsider."

Listen to the podcast from Martin's Radio 5 Live Consumer Panel slot earlier today.