Hi I have received a gas bill from Npower for my old address for over £700. I left my previous address in Feb of this year and we recieved a letter dated March 2009 saying we were in credit £30 with Npower, I contacted npower to close account and get refund and sent them a copy of the front page of my new rental agreement as confirmation of new address, unfortunately i never heard back and have admittedly forgotten all about it. Today the letter recieved states they have added £7 onto "my debt" as they had to trace my new address!

I know that my previous house has been empty since we moved out as the landlord has put it up for sale, so presumably the gas debt must be an estimated bill on our previous usage.

Will i just have to send proof of my new address and the date we moved in and maybe a gas bill from my new house to get npower to close my account?? Also will this show up on credit file as my debt even though its not mine??

Any help appreciated- thanks