Axxess and MTN are useless at providing support for the products they falsely advertise

I have been a satisfied client for more than 15yrs and am at the point of calling it a day with what once was the best ISP in the country. I have a fixed LTE Pro MTN 100mbps line with a 1000gig FUP package which I pay R779 for every month for the past 5 months. I was very happy with the product up until 2 months ago when suddenly my speed dropped to an average of 2mbps. Numerous support tickets logged, support non existent, taking up to a week to respond, back and forth with do this, do that and eventually getting the fault logged with MTN...and here I am still waiting for feedback from MTN...Axxess keeps closing the tickets due to no response or activity because they take so long to attend to the tickets. They have become more and more useless over time. I must pay for something that they advertise and when I don't get what I am paying for and ask for a refund or reduction based on the service received I am told sorry they don't guarantee the speed of the line and that there was data usage.