Cell c and its bad services

I took a data sim only contract with cell c which the was a special and i was paying R178, when my contract ended i was not made aware and my debit order amount increased to R320 automatically and the method of payment was changed from debit order to manual payment. Not being aware that im supposed to pay manually, my account fell into areas and it affected my credit score. Last month (August) i called and told them I want to settle and close the account completely but to my surprise i get an email saying that i owe R320 for the current month (September) and when i settled the account i was told the settlement was the last payment but the contract will close after 30days but I will not be paying any amount.

If i knew the time i took the contract I wouldn't have taken it, cause now it has affected my credit score and as well as my finances Yersteday when i called to enquire about this, the lady said she doesn't know why I was not made aware that my contract has ended and she cannot answer me. Call ***