MTN - No service and no one interested - CUSTOMERS PROBLEM

I have been without network coverage for 3 weeks at my house which also serves as a home office. Although i have been a loyal customer for 17 years MTN in not bothered to assist. This despite numerous phone calls from me to Network Coverage - i was issued a reference number and was even contacted and an appointment was made with me so they can investigate. No one showed up and i am still waiting for an excuse or a new appointment. I went to MTN in Summit Road and again was passed from pillar to post between network coverage and retentions ( i want to cancel this contract due to no service available to me!!) . I was told that i need to obtain a letter from network coverage detailing that there are issues in my area so they can cancel at no cost or pay R6300!! How do you get a letter if no one is interested in your problem??????