Car Seat Belt Not Working on New Used Car from Honda?

So I bought a used Honda Civic directly from the Honda Dealership here in Ontario Canada.

The car was Safety Certified and Etested with a full point inspection check from Honda, then when I brought it home the seat belt does not work!

Its just stuck and won't move no matter what I try, so I wonder if Honda claims to have done Safety which has to be done by Law Government standards.

What should I do? Return the car or just get them to fix it or get a lawyer and get something out of it?

Appreciate any feedback you can provide.

Take it back to the dealer and get them to fix it.
Make sure the service manager knows that they have not done their job properly.