Mtn is the worst nightmare

I requested to cancel my contract last month and I was sent from pillar to post I went to the Mtn shop in Newtown mall and they advised that I need to call after I was quoted an amount for cancellation I paid the amount however I received a statement on the 14th of July with a credit balance I have since been requesting for a refund till today , I spoke to billing and retentions department no one can seem to help and it’s been over 21 days that they advised me to wait Mtn is by far the worst service provider when calling in to the call centre it seems as if you’re disturbing their peace please look into this horrible service