Legal Info: What is my recourse?

I am a serious photographer and have some of my works on Flickr, under a limited Creative Commons license. The terms of my license state that my photos are free for use for all non-commercial purposes, as long as attribution is given.

I’ve been solicited a few times to have some of my photos published; this last time, a contractor/freelancer contacted me and said Microsoft wanted to use a photo for their student portal and were willing to pay $150. He was very persistent and eager to have me sign the photographer and model releases, as well as have my subject sign a model release.

I did this in December and faxed it to the contractor, but since then I’ve heard nothing. I emailed him a week ago to check on the status of this, as I have heard nothing and have not received my payment, but he did not respond.

I don’t want to assume the worst, but the idea of having my photo “stolen” like this is really aggravating. What compounds the issue is that the contractor lives in California and I’m in WV.

I’m wondering how I can proceed, if indeed they backed out on their end of the deal. Any advice would be appreciated. Thanks!