Based on your description it sounds like the FIOS people are covering their butts by blaming the Sony. Being a Verizon customer myself, I'm less than thrilled with their support system. The fact that they never sent you the patch may be telling.
You've probably already bought a new TV but if not you should start by asking the FIOS support people what TVs are most compatible with FIOS and won't cause problems. If they hem and haw about making a suggestion, you can probably assume the problem you had was with FIOS, not your TV.
Our Sony Bravia KDL-40S20L1 tv had a beautiful hd picture. It worked with Direct TV. When we got the Fios fiber optic cable, we couldn't switch from regular tv to HDTV without the screen going black. We had to change the input to regular tv before changing the channel to an HD channel. if we forgot, the screen would go blank. The techs at fios fiber optic cable tv said that there was a glitch in the sony bravia KDL-40S20L1 that needed a patch from fios. We never got a patch from them. It has been going on for one year and four months as we have a 2 year contract with fios. Our TV had such a beautiful HD picture that we didn't want to give it up. Now, I think that all the switching back and fourth and changing the input and mostly the forgetting to change the input has damaged a chip in our tv. We have a blank screen with only a slight blue glow. We were told to get it repaired by a sony repair person, but we are afraid we will have the same trouble after the repair. Should we buy a new, different tv or get this one repaired?