All of the work is done at this point. And I am a bit confused, as I'm based up in Canada and they're in the U.S. We don't have 1099's and W9's here from what I understand.
Sometimes companies will require that you certify that you're a foreigner using a Form W-8BEN. If you're not able to resolve this issue with your client by explaining your status and it's creating issues for you, you should consult with an attorney.
It also sounds like it would be worthwhile for you to consult with an accountant who can educate you about your obligations to your clients and your subcontractors generally.
Also, I've already been paid in full. So at this point I have nothing to lose really.
At the end of the year, it was simply recorded as a sale and was taxed appropriately.