Why are channels pixilated & distorted?

I've had 3 techs come out in the last month and do different things that have done nothing to solve my problem. I've been having periodic pixalation and freeze frames for the last year. I copied the following from a forum that pretty much sums up my problem:

For the past year, our cable signal becomes very pixelated and freeze framed and sound outages. It started when Cox opted to require cable boxes for every set in the house. Only it's affecting sets with and without boxes. When service is called, they attempt to be helpful and apologetic but enough is enough. It takes a minimum of two days for service to arrive, they reset boxes, put more filters on the lines, and leave. It works for a few hours, sometimes a few days, before it starts all over again. I live in a new residential neighborhood in a newly constructed home. After 26 years of loyalty to Cox, I'm ready to try something else. The last guy even replaced the drop line to no avail. One tech put on filters the next one took them off, each one has reconfigured the wiring on the amp to their specifications with seemingly no regard for any standard. They just look at things and scratch their heads and leave thinking they fixed it, which they have not. Pretty much ready to switch to HULU at this point.

Disappointed and frustrated beyond words.