Non existing LTE signal

I signed a 24 month contract with Telkom for LTE and a router on a 50GB day and night surfer package. When the signal was tested it was impressive (30 download / 18 upload). After 6 months the signal speed started decreasing. After another 3 months the signal has gone down to non existing. There are times that the Task Manager on my PC shows zero signal for 15 minutes on end. This is always the case with Telkom as they start to either throttle the account or add to many devices on the same tower/exchange. I have phoned Telkom 10 months ago and only received feedback that a technician will call me and come out (I am still waiting for that call). I have emailed the Telkom agent who sold me the package (Kevin Archary) with no response. I will DEFINITELY not renew my contract again OR sign any other contract with Telkom as they are pathetic in after sales service, problem resolution or responding to calls/emails.