T3 Time-out Error

I have recently purchased my own modem and router. Since then I have begun to have internet connectivity issues. When I log onto my modem I am seeing numerous T3 time-out errors. I was having drops at least twice an hour. I have been through three modems and have most recently installed an active return amplifier to help with the power levels. The most recent modem and amplifier have seem to help a little bit. I am getting the error still but not as often and as a result am not seeing as many internet drops. I had a tech come out who said everything was fine. However, everything is not fine. I am frustrated that the service I pay nearly 100 dollars a month for is not working reliably.

How do I get the tech support I actually need to take a look at my issue?

Thanks for any help or advice that can be provided.