MTN Contract Cancellation

MTN not willing to cancel my SIM Router contract. Sent an email to their Retentions Dept, complained via Facebook platform, also called them and was holding for close to an hour with no answer. MTN on Facebook advised that Cancellations Dept was going to call me or email me the cancellation fees, and that was two weeks ago. I have been following up and now I'm exhausted. Poor service.