R4000.00 which cell c claims i owe them

The cell c sales agent called me and offered me a prepaid sim , only to find out it was a contact . i called on 24 September 2021 and request them to cancel the 2 contracts . the Agent i spoke to he said he canceled the contract and they wont be a need to pay a cancelation fee.

A week later i wanted to upgrade my line , i was told i owe R 4000.00. i called the customer service i spoke to Mboyani Motsetse she failed to assist and she hung up , i called again spoke to Thandeka Mohlala she refused to send the statement and i requested to spoke to the manager . Thabang the Manager refused to talk to me.

i wanna why did they tell me about the outstanding balance i want a break down of R4000.00 and why are they refusing to send the statement.