Being ****** by Cell C

I was having a contract with Cell C that was suppose to end last year (2021)November. On August and September they did not make their debit n I got into arrears,but October they had debited for 3 months which was R1414. They started with R966 for previous unpaid 2 months and R448 for the current debit. I felt relieved coz I knew that only one month left for me with this contract but suddenly the great disappointment occured. Cell C did clear the arrears in my account and when they send me the statement I still owe that R1414 I started to launch the complaint via email asking for bank statement and I sent them. After sending them all the evidence that I paid that amount they have stopped responding on my Emails. Please help me guys beacuse the debt keeps on accumulating when they send me their statements