Two weeks late I find this post - mea culpa!
I'm still hung up on this (still reading):

It would take astronomical amounts of time and effort to modify the product he sent for it to be viable, and we’re just not willing to spend any more thousands right now on developers who may or may not be capable of delivering ...

Do the right thing, developers!

If you sell something and it doesn't work, issue a refund, or make it right!
agitating for yet another hopeless cause, I am, but dammit I want to see issues like these resolved, not some dev moving on to the next... uh, "customer."