To contact Verizon, you can either call or use the online chat.
The number is 1(800)VERIZON or 1(800)837-4966
To reach chat when available, use your mouse pointer to hover over the Support tab at the top of the page, then drop down and click the Contact Us link beneath the Account Help column. Then answer the questions.
To attempt to make sure that the issue is not on your end, I would stop and then resume the movie. If this didn't help I would perform an STB Auto Correct. But chances are it is an encoding issue on Verizon's end.
I was watching an episode of The Voice in HD and there was recurring video jitter and occasional audio digitization. It was very slight, but annoying. Your issue sounds like the movie is unwatchable. If you paid for it, make sure to get a refund.