Contract end with continued debit order

Contract ended last month with mtn and debit orders still going off. I've received one call that I missed and no attempt to call me again as to find out what my plans are with the contract. My contract is for a portable modem and data so how can you still be debuting me the same price if router is paid off? I've tried numerous ways to cancel but there is no way for you to get hold of a mtn consultant. Even went in store and they too just gave me a number to call that doesn't help me. Customer service is pathetic but they quick to take your money. Also their network is not good, alot of places where signal is bad. Can you please just stop my contract because I haven't even used a single mb of data for the last 2 months yet you taking my money.