1 star is way to much credit for Cell C

I got a contract with Cell C for a P30 Lite, I was paying R377 a month, which is incorrect because I didn't sign a contract for that amount, with that said, I left it and continued to pay it, I then started paying my contract via Eft from FNB, I contacted the call centre and even went into a Cell C store and I was not told about this, so what happened was, I then started getting billed R448 a month and now suddenly R480 a month, I then called the cell c customer care to find out what is happening, the lady then told me that because I don't pay via debit order, I get billed for the debit order I then asked to please speak to someone higher because I have never heard of this, it was never ever discused when I had gone into a store when I had called the customer care for a reference for my Eft, I then spoke to another consultant who had told me that the bill was R70 for the debit order that did not go through, so if it was R70 then why was the amounts for the months differentiating, I then proceeded to ask to change my payment of method because I was unable to do a debit order, then it was said that ONLY RETRENCHED PEOPLE HAVE THAT OPTION???? she then proceeded to tell me how I can pay it on the 25th and then when they do a debit order they will see it has been paid and I will not be billed? So uhm, I do get paid on the 31st, how is that possible? Please let's all bear in mind that I have a contract with MTN, and I have never ever had this problem?