After having three HTC ThunderBolts, since the ThunderBolt inception, March 2011, spending numerous hours with tech support, I have finally came to the conclusion; luckly I have only a one year contract with this phonel.
Verizon + HTC Thunderbolt = Tech Support = Sorry I can't help you, Goodby, = Goodby Verizon Hello A.T.T. February is not that far off.
I accept that this is not the best solution, however it appears to be the only solution available at the present time.
Verizon network more than likley not the problem, although the ThunderBolt is by far the worst phone in the twelve year experience with Verizon.