I am sorry Cricket.... that is all I can say. Why not try and write, or re-write a letter stating that it is immoral for them not to pay you. At least get that off your chest by writing to them.
I had a company that did not want to pay me, due, to the fact that I could not edit the report in time as it was a holiday/vacation season. It was a $36.00 job. After my letter of pleading and complaint, they did surprisingly pay me. I knew it was a good report and they still were going to use it regardless.