MTN Fixed LTE is Terrible

Signed up for MTN fixed LTE with ZTE router. The 1st 3 months was a dream . Good speeds, available during loadshedding. Then the nightmare began. I work from home and cannot work with the speeds I get, especially from 17h30 till around 21h00 (barley 1mbs at times) I have logged calls and they established that the network speed is acceptable (********) I feel that I am been charged for a service that is virtually non existant when I need it the most. A technician was supposed to come and to check. 5 months later, Im still waiting. Dont take fixed LTE with MTN. I have normal phone contracts with MTN and have to use that to hotspot to get better speeds. I have used the LTE Sim in my phone and clearly the tower that it is locked to is way too busy at these peak hours. Sort it out. PS I will not renew any of my contracts if this is not sorted out.