npower bill problem

i recieved a letter from a debt collection agency this morning saying i owed npower 400 ish pounds for outstanding electricity bill from previous address.

when i moved out i got final bills as the npower gas was in my name but not for electricity as wasnt in my name and their were other tenants in the house

i paided the final bills and left i redirected my mail for 6 months never heard from n power, when leaving old house i left my contact details with tenants still there incase any bills came in never heard anything.

i called npower about this bill as it was never in my name they said the landlord put my name on the bill and they didnt ask him for proof or confirmation that all i lived there

also all the bills and letters from npower never had my name on hense no mail was ever recieved by me or erdirected to my new address

now they say the account was transferd to me and i am liable for the amount even though they never contacted me about putting the account in my name or ever sent the bills in my name

how can they transfer the account on someone elses say so and not even notify me . then make me liable for it

i ve told them that there was 3 other tenants at that time and i m happy to pay my share and i m having to go through citizens advice to sort tennacy agreement from old landlord


can npower just change accounts to other people on a strangers say so ?

also what would you recommend to do in this situation

npower wont even discuss it