********* Debt Collection and poor customer service

I have been a client of MTN for 20 years. For the last 10 years or so MTN will periodically hand me over to collection agents for a supposedly arrear account. The sums are always ridiculously miniscule (between R350 and R550). I have made several attempts over the years to get to the bottom of this to identify the source of this account to no avail. I have emails dating back to 2018. Their customer service and legal departments are manned by a BOT and when you do eventually get an email response, you don't get to engage with the same individual so you keep bouncing around telling your tale to multiple people. And because the quantum is so ridiculously small, nobody prioritizes your complaint. However the potential damage to my credit record is immense if I ignore these debts. I have now paid another one but I know in 3 years time I will get another call from collection agents and start the cycle again. My primary phone account has never been in arrears in the 20 years I've had it so they continue to call to try and upsell me on products but not a single soul is prepared ACTUALLY provide the ethical customer service I require and need.