... Why isn't the Contractor coming back? Obviously, he hasn't finished the job. And hopefully, you're witholding final payment.
If there is/was a heavy smell of 'petroleum' in the house when the poly was applied, it is oil-based poly. If the smell was much 'sweeter', then it was water-based poly. Also, if the installer put on 2 coats in 1 day, chances are very good it's water-based.
I think you need to ask the contractor who is going to finish the job if he isn't. If you plan on going to court, you need to backwards-document all that happened with names, dates, times, and details of everything. Because if you have to have another contractor finish the job, and want to get reimbursed for it, you need some 'history' of what went on. Also, the judge is going to be sure you gave him REASONABLE OPPORTUNITY to finish the job. If you don't, the contractor can change his story. This is why you need to use things like Certified Mail, Return Receipt as well as a log book. If the last coat doesn't go on real soon, you will NOT get a good finish. Right now, if you're walking on it, you need to stop. All kinds of dirt and grim are being tracked on it directly AND indirectly. Start calling and writing fast.