My contract is different from what was agreed on the phone
I agreed a new 12 month contact with the retention team at £34.00 per month. I've just had a bill for £54.00 taken from my account for the first month. I checked the new contract in my email and it states that I'm now in a 12 month contact at £54.00 per month. This is not what we agreed! How do I get my money back and make sure I'm on the £34.00/month contract?