Unauthorised deductions

I am so annoyed. I registered on the Edcon website to allow viewing of statements and by chance decided to check deductions as I normally simply pay whatever the installment may be. It was quite disconcerting to notice that I was being billed for an airtime contract that I was not aware of and did not enter a contract for such. I then decided to check the other months and lo and behold i have been billed for an airtime contract plan for the past 2 years. I called the call centre in an attempt to resolve this only be told by the call centre they cannot see the deduction and I might be looking at "interest charged" Really!! thats the best they could come up with. and I am told that the contract was terminated December 2017 even though I have a statement reflecting airtime contract deduction of R129.00 , 06 April 2018. I printed all statements and highlighted the deductions but yet I cannot get any clear answers from the call centre via email or calling. very frustrating being sent from pillar to post