Incorrect Billing/Pathetic service

I cancelled my contract for Cell C in June to be effective on 20 July 2020. Cell charges you in arrears whe you have a contract which was fine because you receive you data in the begginning of the month and you pay at the end of the month, however in July they provided me the full benefits of the contract and I paid the full payment at the end of July because of the benefits. At the end of August I get another bill from them but have not received any benfits so I called them to find out why, I spoke to Thandeka who advised that it is a pro-rata charge. I told the agent that I did not receive any extra benefits other than what I already paid for and then she claimed I purchased a bundled then I told her no the account is capped at R0 so nothing can be purchased. she puts me on hold without telling me then comes back and says no its a pro-rata charge. Then I explain to her what pro-rata means and she says please hold I am going to transfer you to the dispute department only to end my call without a resolution. A week ago I spoke to Busisiwe who confirmed that there will be no charges on the account and that it is fully cancelled.

Cell C has pathetic customer service and I expect a call back from a manager to get this sorted