2500 dollars is a lot for me, in my current situation. Surely it's not morally questionable as I paid for a service, to be completed at an agreed date at an agreed price. If he refuses to stick to the deal then I don't see how its amoral for me to pay him the 2500 dollars and keep my software, even if he wants to try and squeeze more money out of me.

Please feel free to let me know why it would be wrong for me to do that, as I'm not trying to be unethical.

Also: corrected the dodgy formatting!