erroneous billing

I don't have any cell c account, nor mobile vault back-up subs as well as credit life personal insurance. I did not take anything on credit since Jan 2020 to date, however they keep sending me invoices with irrelevant information. I made a numerous number of calls trying to figure out the R925.92 said to be owed by me, and i am not getting any joy. I have been paying the account trying to make peace by closing it, still i am not winning. Recently, calls are not even responded to. I feel betrayed. Kindly intervene as i have hit walls in trying to get this problem resolved.