Frustrated Client

Cell C has been Harassing me with calls claiming that I am in Arrears for the month of July 2022. I have disputed these claims and sent several emails to Cell C providing proof of payment. I was given 3 different email addresses by 3 different consultants to email my Proof of payment and for the whole month of August I have been doing that. But the issue is still not sorted out. Instead my account statement still shows that I am in Arrears and they are charging me for this. This is unfair to my account and to my credit reputation. I do not appreciate the reflection it has on me for the fact that I know I paid to thier account that I use every month and with the same reference I use every month. I have been emailing them but with no luck of response or a way forward. They are harrassing me asking me to pay the amount that I already paid. That is not going to happen!!!!.... I can not wait to finish this contract with Cell C and get the hell out!.. they definitely lost me as a clinet.