Greetings Scott welcome to the Forum.
You mean you checked the HiVoltage, and it was ok?
Did you check the Control Voltage too, Stats can click and still not have power to turn the system on. Find the little Transformer and see that it has about 24VAC (usually).
Could be someone stepped on a wire or something like that, or there may be a loose connection somewhere.
You ought to contact Goodman, and see what your situation is, given your Installer has disappeared. Maybe they can give you an alternate source for help, IF you need Warranty repair.
Have a good Day !
S.W.