I'm having the same issues as everyone else with movietickets.com gift cards.
Here is the real issue, they were bought by fandango in 2017, and have pushed their tickets purchasing over to fandango. Movietickets.com is nothing more than a landing page that redirects to fandango. The problem is that fandango does not honor these gift cards when they absolutely should. Bombard fandango with support emails until they fix it.