As
jtpipkin said, I'd look for the internals and rebuild that valve unless there's something majorly wrong with it structurally.
They sure didn't do you any favors when they installed it.
If you do wind up replacing it, we can make some suggestions of how to remove it. Looks like there are a couple of places where you can cut the pipe and install a union when you go back with it. On the left side you're going to have rebuild at least part of the plumbing for the new valve.