Over deduction for a contact premium

Dear Hello Peter, I signed a contract with Cell C in 2017 where the agreement was that I’ll pay R277 but 309 was deducted from my account for more than 24 months. Recently i again renewed my contract with Cell C and again the agreement was that i pay 277 but R420 was deducted from account. I was told that it is the arrears for the new contract that was supposed to have been deducted in September so the R420 is the payment for September and October, the very same month of September I paid 309.Cell C is reaping us. All this extra R20 deducted from your account for 100000 people is *** a month Please help me get my refund for the over payment from 2017. Again they will give you a big number of data but their network is always not connecting, the following moth you forfeit all unused data. I came to think that their data is just a number on your balance and nothing else