over charged for something i didnt sign up for

I am loyal customer at telkom but now they are ****ing me off every month my bill increases last month it was very high and i called in and they told me about a line that wasn't on prepaid which I didn't authorize i told them to change it for me they did and they told me that my bill will be correct this month but now i recieved a SMS with my bill higher then last month and i am ****ed cause i feel l have been paying for something that i didn't pay for who ever is changing my stuff at there office is ****ing me off i wanna cancel all my contracts with them cause they make me over pay for things i didn't authorize kindly assist cause i have been waiting for a consultant for 2 hours now and thats also ****ing me off cause monthend they will deduct that money