Incorrect debit order dates

My contract has been with cellc for over 10 yrs and I have never experienced poor service up until this year April. I was double debit in the month of April on the 1st and then again on the 30th. My debit order was scheduled to go OFF on the 1st of every month. I contacted the call center immediately and they acknowledged it was their error "Kindly be advised that this is a duplicate case. Please refer to case number ***" and requested I send them a bank statement ad proof, which I did forward to them. Then again in May they tried debuting me on the 4th, 14th and 25th resulting my account being overdrawn and fees fir returned debit being charged. I again contacted the call center and was advised by the consultant that it was cellc error and the fees will be refunded to my account and the date rectified. Then again I was double debit for June the 2nd and the 7th when the payment was already made. Again this resulted into my account being overdrawn and fees charged. I then received the below response "Please note in order for us to change from direct debit to cash we need supporting documents. It can either be a retrenchment letter, letter of unemployment or a letter from your bank confirming your account is closed." I sent them a sworn Affidavit indicating I no longer have a bank account and I'm not employed. This was in the month of July. I made several calls to the call center with no success and then my line was blocked. I once again sent email communication in September to make the relevant arrangements to bring the account upto date and rectify the issue with no success, my emails were simply ignored. I sent another email October and received a response on the 13th October indicating my request was dispatched to the collection department, again no call or response from cellc. Cellc was was very quick to send me an account statement on that then in dictated I owe R11600, and my contract canceled. This too was not communicated to me after I made several attempts to contact cellc and also rectify my account. I would appreciate if this account can be rectified as this contract was canceled without justification and valued reasoning.