Refuse to assist with contract.

I was called to renew my contract and was given a good deal, now they charge me full price after i called customer service last month and they said that it is only for the first month. I sent an email again yesterday and they said that there is no mistake and i even included the retention contract in my email. If this is the case, this would be the last time i renew my contract with them. The best of all is that they said because i am already a customer for eight years, that is the reason why they give me the good gontract deal. Seems to me i have been mislead. Beware.