CELL C PAID UP ACCOUNT STILL SAYS IN ARREARS FOR 5 MONTHS

I canceled my contract and it paid it off with Cell C and they handed my account over for R300 on the 4th of September 2022 to SSDA debt collectors and on the 6th of September 2022 I had to R450 to them and they promised to send me a proof of payment, till today 6 Feb 2023 I haven't received the paid up letter from them and my account still says I'm in arrears. When I go to Cell C they tell me to go back to SSDA and SSDA tells me they are waiting for Cell C, I feel like I'm being played and my credit record is being messed up.