A few months ago, I have the same problem with British Gas. But I have made a call to British gas customer service for the help. They guided me very nicely and tell me each step very clearly.
If you want people on the end of the phone who take the time to listen, understand and have the skills to fix a problem then you need to go here www.alwaysreview.net/reviews/british-gas-contact-number/
Being quizzed by chemist's assistant in Boots.
Feeling uneasy with tradespeople in the house.