Disappointed Customer

I am really disappointed with the service I received from Cell C.In December 2021,I decided to get a contract with them. My understanding was that the contract was on a month to month basis, because it was advertised as such. To my surprise, upon calling to discuss the contract, I am told that it's a 24 month contract. Secondly, Cell C has increased the contract amount without notifying me. Aren't cellphone contract amounts supposed to be fixed for the contract period? Also, the amount being charged on my account is not the amount I signed up for. Customer Care said they won't be able to help me in anyway. Now I'm stuck with a long term contract that I didn't want for another 12 months.