Npower can continue with its outbound telephone sales after meeting the first set of targets set by Ofgem, the UK energy sector regulator said Wednesday.

The supplier, the most complained-about energy firm, had been warned by the regulator in June to either reduce late bills and customer complaints by August or stop selling contracts on the phone until the problems were resolved.

Sarah Harrison, senior partner in charge of enforcement at Ofgem, stated: “Ofgem is encouraged to see that Npower has met our targets aimed at reducing late bills and we note their progress on reducing complaint numbers. But this is only a first step to turning round their customer service and billing performance.”

Ofgem also opened an investigation into the problems the same month and had been monitoring its service closely.

“We will continue our investigation into the reasons why Npower’s problems occurred,” added Harrison.

Npower received 1.4 million complaints in 2013 as it struggled with errors caused by the introduction of a new billing system. The number of late bills that were sent out by the company fell to 62,000 in August, compared to 280,000 in June.

The target set by Ofgem was 100,000.

The number of complaints received by Npower also fell to 99,799 in August from 120,016 in June. Npower had received more complaints than any other energy firm in every quarter since October 2012, according to figures compiled by Citizens Advice.

Roger Hattam, Npower’s domestic retail director, said: “I’m pleased that we have met our commitment made in June to reach our billing performance target.

“We’re now billing over 98 per cent of customers on time. However, the journey doesn’t stop here as we’re working hard to make even more improvements.

“For example, we have reduced complaints to the Ombudsman by over 70% since June, but this is an area where we will be doing more. This is our own commitment to our customers.”

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