Complain about a debit order of a cancelled contract

I have been waiting for q refund from 1st of August sent emails whole month and called wasting my airtime whole month, come month end I get another debit order while I cancelled the contract and while waiting for a refund that I was promised,now I'm getting SMS that I won't be able to use my phone I'm will loose connection till I pay MTN while they the ones that owe me and I have been waiting for a billing dispute,I sent a text on bellow Peter last week and still didn't get a call now I have another problem instead of this one being solve!