Cancel service and want the correct final bill

I cancelled my account on 2015/12/01 at Telkom Potchefstroom with all the right documentation. (It took 51 minutes to do this). Everything was paid in full. <br> The next bill 6 Des(for Des charges) R505.52. No cancellation.<br> I called 10210 and hold the line from my cell phone for 16 minutes and dropped the line after no response.<br> I visited the Telkom shop again and told them the account is still active. (Again I waited 47 minutes to do this and they told me it is cancelled and could not give me any proof that it was cancelled. I asked them to suspend the account because I knew it was not cancelled)<br> Next bill 4 Jan R1010.45. No cancellation<br> I called 10210 again from my cell phone and they told me to send a email.<br> I send a mail<br> They called me and said they will cancel the account.<br> 4 Febr next bill R1464.15.<br> 10210. No response<br> 4 March next bill R1258.74<br> Hopefully the account is cancelled but now the amount is wrong. <br> Please help to resolve this matter.<br> Please make sure the account is cancelled and send me the final corrected invoice, and don't blacklist me.<br> The service was stopped and was not used from 1 Des 2015.