MTN CONTRACT CANCELLATIONS

My contract (Account number A***) was opened on 23 March 2018 and has since EXPIRED and never renewed, the line was disconnected but MTN is STILL debiting my account TO DATE. I have gone back and forth with MTN and I have been unable to successfully cancel it even in store. I was told to contact MTN Customer Care, which I did. I was sent from pillar to post by the call centre agents!! MTN, PLEASE STOP DEBITING MY ACCOUNT. I cannot continue paying for a line I am not using. The line was probably given to someone else already. PLEASE ASSIST