SWITCH FROM BRITISH GAS ASAP! I had a pre pay meter when I moved into this house and like you had problem after problem, was on the phone on hold all the time which cost a fortune! Everytime I added credit it took a chunk out of it, the person before me had debt and I was paying for it

so I let them know, they siad it would be sorted but it continued to take money off me!
Then I got a bill for about £160 .....after 3 weeks!!!!!! Again this was the other persons debt! so I rang they said it had been sorted and Id have a corrected bill, the "corrected" bill was £220! so it increased
meanwhile they meter was still taking money from me, which I was told Id recieve a cheque and I didnt.
In the end I changed it to a normal meterso thatI could leave british gas, Id never never use then again!