Deliberate refusal on customers cancellation request on contracts

I paid up my cell c accounts last year April 2018 due to resignation and requested a cancellation on both contracts. They promised me all is ok. This year i started seeing deductions going off my account and i reversed it. When i queried it with cell c they gave me long stories. I followed up numerous times with Cell C and even went to the store for help, but to no avail. The last call centre agent said that the store has made the mistake and that they should assist me with this matter. He said that the store should call Credit control department in my presence and the Store Manager said he will handle the query himself. The Manager at Trade Route Mall "****er" would have followed up and called me on Monday, 1st April 2019 and to date i haven't received any phone calls from him yet. I'm very frustrated since the mess up started at the cell c store in Trade Route Mall. I paid nearly R8,000 settling two contracts and they did not even cancel it as per my request. The Manager has requested that, i pay the outstanding amounts and i refuse since, if they had done this correctly i would not have had any amounts outstanding. I knew i would not be working anymore therefore i paid up these contracts and requested cancellations. Cell C Refuses to cancel contracts so clients must remain liable for contract payments. I want all unauthorized payments to be reversed into my bank account and my contracts to be cancelled with immediate effect. Please help..... Cell C sucks.....