Check the lights on the ONT. They will tell you if you have service. If the lights show you have service, double (triple) check the cable between the router and the ONT. If you used to be pure coax, you might be on Ethernet now. If so, you'll need to install an Ethernet cable between the two.
If the lights indicate no service, something is wrong in Verizon's system. Try contacting their social media support team via @Verizonsupport on twitter or https://www.dslreports.com/forum/vzdirect. They are typically more helpful than the front line support folk.