This is a **** and ruining my credit

I had a contract with Cell C for years and it ended in 2019 Cell C keep debiting money from my account. When calling the call center no details found under my name or ID, but no explanation as to why am I debited. This is messing up my credit record. I was told to email to collectionqueries, debtreviewsandadmin, legal collection. The response was that am owing and I need to settle the outstanding amount to avoid handover. how I do I owe an ended contract. Where is the statement then. Why details are not in the system?This is also happening with my father, now we have to keep reversing our money?