Chronic slower speed and buffered than CenturyLink DSL

I changed from DSL over the landline to Viasat on April 23 2014. I made this decision after looking at other satellite internet providers and decided Viasat was right to me. I have the Unlimited data plan. The installer did his job and connected me quickly and I was off and running. As soon as I began using the service it became obvious that it was much slower than I was expecting. I had purchased the modem from Centurylink and it surpasses recommended modems so I was able to pair it with my Viasat modem. It was only
A slight improvement. A few days later it was so slow I couldn’t load any apps. After calling and rebooting my modems the found something off and sent the installer out again. The installer was insisting that he was only an installer and could do nothing about speeds. After checking he found my antenna was off beam and he readjusted the dish and said everything was working perfectly.
Speed check was good but in real use it is still slow.
After calling tech support they said my dish receiver had been unusually hot and scheduled another visit from the same installer who does nothing about speeds. It just so happened he was in the area and called me this morning and said that he checked my system and it was perfect.
That he would come back out on the scheduled day but there was nothing he could do as he never heard of overheating as a problem before.
The slow speed continues.
If I cannot get the speeds and service as expected or if the engineers can not troubleshoot and fix this then they can come back out and get this crap off my roof.