NO to Cell C

I had an Cell C contract for over 15 years. Always issues. I recently decided i had enough and wanted to cancel my contract at end of contract term. I called gave notice 3 months before end date and after that every month till contract ended. Now getting calls from attorneys account handed over 1 month after cancellation? sent all proof of payments. Now I check my credit score... "missed payments since 2021" only 2 payments received the past 2 years? How can they list you like this even after payments reflecting on my Cell C statements confirms that payments was received every month. Never ever again.