breach of contract

My name is Nthabiseng I've been a Cell C client for 8 years now but the service I'm getting from them now it's pretty messed up,I have a 2 contract with them and we agreed on their contract that they will debit my account on the 28th as it is my pay day each month but they debit my account if not early or on the last day of the month and they find money on my account they penalised me I pay extra cash and last month August they say i didnt pay one of my contracts but they debited on the 26th and 31th and took extra for penalties which July but I payed both contracts that month and thursday i went to one of their store to query about this the staff member doesnt have an explanation as to why they say i'm in arrears and why they suspended my contract and i also send through my bank statement but they say they haven't received it and i keep calling customer care but i'm not getting joy they keep transferring my query to different people but there is no feedback and now I have to wait Monday for them to call me back,but I know I will be the one calling them.So I'm not happy with their service at all and my contracts are due in November they will not see my business as im taking it else.