Mtn ***** debitorder

I app**** for a contract phone with mtn and it was declined. However the next month a debit order started going through my bank for a sim card which i never asked for or authorized. Since then i have to return the debitorder and carry the bankcharges for doing so. Disgusting and ******** to do so. Now my sim is blocked and i cannot use my phone purchased from another company.Can someone from mtn call me please to sort this. ***