My SIL and her hubby bought a flat that had previously been a buy to let flat. The previous tenants had run up a couple of massive gas bills with British Gas. Before they moved in, the gas meter was removed, so there is NO gas going into their flat.
They have had about two letters a month for the past two years from British Gas!! SIL's hubby phones them every so often to ask them to stop hassling etc etc. They can't seem to get it through their heads that the previous tenants have moved out and - more importantly- that there is no gas in that flat!!
British Gas have threatened them repeatedly with a 'man' who will come up and CUT OFF the gas supply and SIL's hubby keeps telling them - you go right ahead, because then maybe you will discover that there is NO gas in that flat.
2Years this has been goin on, and it seems like it wont stop anytime soon.