Annoying MTN provider

I've been trying to cancel my contract with MTN for a month now, went to their store at Westgate mall and was advised they don't do cancellations at the store and needed to contact their customer contact center number 135 I've been calling in since and Everytime I get transferred to the retentions department for them to cancel my contract and advise on the cancellation amount thier line somehow gets cut-off and nobody seems to have an answer to that.... Can I just get my damn contract cancelled and you can stay with your pathetic service!!!! 😡😡😡