MTN is very ********* when you want to cancel a contract!

Towards the end of my contract I called MTN for 2 months straight trying to cancel it. They never picked up the phone but when i selected the upgrade option they answered immediately. I then explained that i can't get through to cancellations and asked if they could assist and they rep**** by saying that i should contact the cancellations department even after I explained that I can't get through. Now they sent debt collectors on me because i stopped the debit orders from after the contract ended.