Paying for no service

I had a contract with MTN that ended in February, I have sent emails on the retention email address with no response on their side to cancel the contract since debit orders are still going off. I have sent messages on the Facebook service last month with no response still. I am not in South Africa at the moment so I have asked a friend and family members to enquire on my behalf in the mtn branches but no one was helpful saying that I need to be there. I am not receiving any service from the provider but I am still paying. Need this to be sorted out soon.