[socrates1998]

You used his code in some respects even if it wasn't in the final product.

If nothing more, then you knew what not to do or what was difficult to do.

Regardless, you probably should have paid him.

It all depends on the nature of the contract. If it was for services and not for a completed project, then you absolutely needed to pay him. If it was for a completed and usable product, then you didn't have to pay him.

Regardless, people here will think twice about working for you.