Unauthorised Debits

About 3 months ago I took a month to month contract with Telkom for R449.00 Per month LTE. Upon receiving my first invoice, I noticed they debited services for which I have not taken. Despite logging several queries, they failed to respond. Also I noticed that while I paid before the time, I was debitted and they added unpaid fees. None of the staff I dealt with did not know what they were doing or could give an explanation for the debits. I was forced to cancel their service. They went on further to debit my bank account without my authorisation on a date not agreed to.