Hi Thomas

I would first start at a second opinion and if you paid for the camera shot you should have a copy , or request a copy of the tape so the nex plumber can evaluate it properly. The trap is installed to prevent sewer gas and vermin from entering your house if their is a bend in your pipe it is not unusual their is sometimes many  depends on how it is run, it sounds to me that you either have a broken sewer main or you have tree roots penetrateing your line this will be evident in your film of the shoot. I also would sugest you check with your township or sewer authority many times they will take care of your line before your curb trap to your street main.

Good luck

Roland Bailey