I'll try to keep this short and simple (if you need to know more detail just ask)
I moved into my house in September of last year (house is rented). we were receiving letters for a tenant who hasn't lived here since 2008. I sent the letters personally to throw estate agents. they opened the letter and told me I need to phone the gas company as they're demanding money. I phoned them and they said they will stop all letters. I then received another letter for old tenant so my sister got onto them on twitter and was told to set up an account and all charges will be dropped (these charges were the standing charges). as our house does not use gas (everything is electric) she said they'll send someone to remove the box. box was removed and was told there was no gas use or going into my house it's been cut off already. I then received another letter saying I need to pay them £71. I still have the twitter conversation proving I'm allowed to have charges removed.