Thanks for all the advice so far. The good news is that we are on a payment schedule which is recommended by the State of Arizona for the contracting board for pool builders. This is 30% after being excavated, 30% after plumbing, steel and concrete has been done, 30 % after the finish, and the remainder when work is complete.

I'll probably call them and threaten to get a new builder and send them a certified letter and go from there. I'll let you all know how it goes.