Telkom will not s**** an erroneous charge on my account which they are the reason for

Telkom will not s**** an erroneous charge on my account which they are the reason for - Black Friday deal last year which they only activated in the new year but charged me one month during time they struggled to activate the phone and I could not use it. The way this company operates is beyond belief. I will never consider a new contract with Telkom until they resolve this account problem and s**** their charge.