Npower says it's improving: its customers say otherwise

He called npower in February and provided meter readings and was told he would receive a bill within 28 working days.

No bill arrived and in April, Mr Mancor received an offer on the bungalow, which had been empty for the whole period. He called npower on April 24 and explained the property was being sold and complained. He was passed to the complaints department which gave him an estimated bill of £404 for the previous 12 months and asked for current meter readings.

On April 27 Mr Mancor provided these. This time he received an estimated bill of £472, and was promised a final bill was on its way. He was advised the total would be higher to include the full 18-month period.

Still no bill arrived. Mr Mancor called again on June 2 to advise npower that the sale had completed and provided final meter readings.

Eventually a bill dated June 17 arrived - for £1,095.39. His mother had paid just £690 in the year to November 2012. The Telegraph questioned npower about the amount, and it subsequently offered Mr Mancor a reduction of £69.34 to reflect the “billing delay” and a £139.66 goodwill gesture, bringing the total bill to £900.

But it insisted the energy was used, even though the property was empty.

A spokesman said: “We have billed the account using readings provided.”

But after months of broken promises and conflicting information Mr Mancor, like many of our readers, has no faith in npower’s ability to maintain accurate records and bill accordingly.

Mr Mancor said: “Expecting me to pay £900 for a house that was unoccupied is absolutely ludicrous.”

Npower has been ordered by the regulator, Ofgem, to tackle outstanding complaints, or face further penalties.

>> More: What next for energy? Should you fix your bill?

>> More: npower and Scottish Power complaints double

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