Investigate Npower for inaccurate multiple billing and threatening letters.

My father recently left Npower and it was a nightmare. He was billed 14 times, each time a different amount. He was sent money, then told he owes money. They were utterly impossible to phone, and seemed to be completely unaware of what they were doing. It was very distressing indeed.

An individual case of this type is not a matter for the UK Government or Parliament. We would advise you to contact the power company. If necessary, you might want to contact Ofgem:

https://www.ofgem.gov.uk/information-consumers/domestic-consumers/making-enquiry-or-complaint