Disgusting treatment, *********** staff and forced interest billing

I saw on my credit report in August 2020 that I was listed by Telkom Mobile for a cellphone contract I had defaulted on (this was all because they have been investigating the matter since 2019 and still no resolution or feedback) and the amount was just under R7200. I contacted the collections company listed on my credit report and they confirmed that my debt was taken back to Telkom since they could not get me to pay within 3 months. I then contacted Telkom Mobile and spoke to a lady by the name of Nokuphiwa Ndlovu who confirmed that indeed my debt was with them and that I can make payment arrangements with her and that we can split the payment into 3 months. I then informed her that I can make payment of R3000 right away and she then advised that once she has received proof of payment she would let me know how much to pay for the 2 following months. I paid and forwarded her proof of payment to her email address as discussed and after reminding her who I was and sending her my ID number for verification, she confirmed that she will send me the amounts to pay. All of this took place within the first 2 weeks of August 2020. Since they I sent emails to remind Nokuphiwa about my payment plan but there was no response. After waiting forever for a response I decided to make a payment of the updated amount that was reflecting on my credit report of R4136,00 on 08/10/2020. I've been waiting for Telkom to update their info on my credit report and still nothing. Today 05/11/2020 I receive a call from some collections company called Debt-In requesting commission from me as if they got me to pay Telkom. This was the first call I received from them and as I was talking to the female consultant she confirmed my email address and sent me an invoice I know nothing about. I request a paid-up letter from Telkom and that they update their information on credit bureau as I have paid them in full. I have proof of all of the above and emails and will report you to ICASA and bring up the previous unresolved case that led you to bill me incorrectly in the first place. Close my account and provide me with a paid-up letter- this is all I ask.