Vodafone are con artists.

Ok so when i got a new contract i was paying like £50 a month and i though ok fair enough i have used the internet quite a bit, i then found out that i had a second 30 day sim. I emailed vodafone and asked them to remove it. They replied with a message saying it had been completed and i would no longer have to pay it. Thinking that was the end of it I carried on paying my bills even though they seamed a bit over the top. I sign up for the online services and see there is a second number on my price plan. I look it up and find out they didnt remove the second sim at all. So i have been paying for a sim i thought i didnt have!

if you ring up and threaten to leave, they usually sort things out alot quicker. particularly if you say yr going to orange.

there's no point threatening unless you're near the end of your term (at the most six months) otherwise they'll just think you're trying that old trick - which doesn't work if you're not near cancellation. If you simply tell them the mistake is calling you a lot of stress and you're thinking about talking to the citizen's advice about taking them to small claims court you'll find out they're extremely courteous and give you a refund while cancelling the sim :)

Take a read at Consumer Direct, it's a government funded online service that offers information and advice on consumer information. As a consumer, you are entitled to rights!

http://www.consumerdirect.gov.uk/

You can do what Bethie said to do too, threaten, especially to take them to court.