Some time ago we had to have our gas turned off for the day while they did something to the underground pipework, so I decided to ring Eon and ask for the 27p daily standing charge for that day to be refunded. They gave me £1.
I find that you must remember a few things when dealing with companies or the government, which are as follows:
1. Be polite and calm: the person you are arguing with is NOT the company, so don't make his or her life horrible.
2. Be firm: don't let someone push you around.
3. Don't get angry at the company: it does not exist, except as a bank balance and employees.
4. Ask for their policy on everything, so that you can quote them if they try to fob you off.
5. Ask for someone more senior.
6. Make them see that paying you is cheaper than dealing with you.