MTN i want answers ref ***

What a Horrible experience with such a BIG well known company. I called asking why my account has not been debited and was advised that the debit order failed due to insufficient funds. i Then made arrangements and made my way to MTN Zevenwacht Mall to make a payment only to be told i have no outstanding balance. The lady who assisted me asked me to sit next to her and showed myself and my dad who was with me at the time the R 0.00 balance, this was in the beginning of February 2021, She then wrote down the dates i needed to call to cancel my last contract...Today i called to cancel and was told i can not cancel because i am currently with the LEGAL department and have an outstanding balance of R 3000 for a contract i paid R 300 a month???? The guy i spoke to in the finance department said he does not know how it is possible that their system showed something else in store as they work on different systems. I then said how is that my problem as you guys are giving me a bad credit profile to tell me one thing in store and another with the call center? Also it does not matter how many different systems a company works on at the end of the day all the systems NEEDS to correspond with each other with client details! i try to keep my credit record clear as i am still young stupid system issues like this should not be made!!! i was then told to clear my name i need to pay the outstanding balance or take it up with the Zevenwacht store Supervisor who is currently closed until further notice. So who do i speak to?? Do i just let the balance run up further, Also the guy i spoke to in the finance department ended up hanging up the phone in my ear after it nearly took me an hour to get through to someone to speak to !!! ref ***