Bad internet service

We upgraded our Vodacom internet contract now 2 yrs ago and we are just getting the worst service ever since. We just upgraded from a 50gb / 50gb wi-fi to a 100gb /100gb Wi-Fi but we are just having trouble all the way. We have been to report Vodacom with ICASA twice already and still no joy! The wifi modem is more off displaying a red button than anything else. If we phone the customer service, they tell us to unplug and plug back in again. On a daily basis I can't tell how many times we do that. The last technician we spoke to said to pull the Sim card out and re-insert it again. Why is this necessary? With our previous older modem on the 50gb/50gb, we Never had such trouble, why now that we upgraded? Vodacom is simply not delivering on their side of the contract to provide us with internet. We are seriously disgruntled. Vodacom is currently the worst internet service provider!