I am not paying a cent more!

I just received an email telling me that my subscription would increase and that has nothing to do with me as I signed a contracted that said I would be paying for 387 including my insurance and I am not paying a cent more. My contract will be coming to an end in August and I am not renewing for such reasons. If you want to increase do so for new contract holders. I cant deal with you. From slow network to this. No thanks I would rather port to mtn or cell c. I have had horrible service from you from day 1 but I remained loyal anyway. This is not even my 1st complaint as I have had a very bad experience with one ****** white guy from the sandton branch and I am rather fed up! If a cent more is debited from my bank account other than what I signed up for I will report you to the CONSUMER COMMISSION!