Mtn refuses to cancel expired inactive contract

Took a 2 year contract out in june 2018, i have requested cancelation via telephone, email, social media and even visited a store to request cancelation at the time the contract was due to expire, but mtn refuses to cancel the debit order, i have recieved plenty of apologies n replies from mtn but this lousy company just refuses to actually stop the debit order.. I can only imagine how many people mtn is *********** and *****ing from in this way... Disgusted with the level of service