I’m told I owe money to Telkom after I paid and completed my contract I keep getting bills that I owe different amounts, I’ve escalated the issue through their customer care and I’m told different stories

I’m told I owe money to Telkom after I paid and completed my contract I keep getting bills that I owe different amounts, I’ve escalated the issue through their customer care and I’m told different stories. I was told I owe September and Dec 2023 but I went through my bank statement and the amount was paid. At this moment I’ve received another statement that says I owe 7000 when asking for a break down on how I reached that amount and what exactly am I paying for as I’ve never skipped a month on my payments they have not returned to me. an amount of 1900 was deducted from my account at some point and did not go through due to insufficient funds I wrote to them again asking why I’m being debited and there was no straight answer