Charged wrong amount on contract

I took a cellphone contract from cell c, they told me ill be paying R170 per month but they are deducting R205.. ive tried several times to resolve this matter but to this day i never got any assistance, ive called CellC so Many times and spoke to different consultants, over 25 consultants ive spoken to but not even one of them has been able to help me. they all promise to resolve the matter but to this day nothing has been done about it... im paying R205 but when i was taking the phone they said ill be paying R170 am i been ****** here or what???