Cell C payment agreement

I canceled my contract in March 2021, they told me it will end at the end of June 2021. Debit orders went off till then as agreed. December 2021 another debit order went of my account without permission, so I disputed that debit order to get the money back. January 28, 2022, I received a call from Cell C that I need to pay that amount. I asked them why and they said because I still received benefits in June, which I don't understand because my debit order did go off in June. I asked them why did I go off in December 2021 then, the lady told me that they did not have permission to take the money from my bank account after June. BUT where did they get the permission to do that in December 2021 then? She could not answer. me. Anyways just to get this off my back I agreed to pay this amount but can only pay it on 15 February 2022 when I get my salary. They agree to it and also sent me an SMS with the banking details and email address where I need to send proof of payment on 15 February 2022. Today, 15 February 2022 I received an SMS that I have been handed over and now have a bigger amount to pay the company handling this matter.

Calling cell C very upset, but the system showed that I am not handed over but they will get back to me regarding this. It's 21:21 pm and no one called me back yet, so what I needed to do was to pay the company the money, because if I don't pay, the amount go up again tomorrow and my credit will be down more.

I think this is very unprofessional from cell C, after the agreement they just handed me over.