I purchased a commercial product in the United States that has user-upgradable firmware available by unrestricted download. I am positive this firmware is based on an open-source project licensed under the GPL. I would like the source for this firmware to make my own modifications, and being under the GPL they are required to give it to me.
I have contacted the company, and initially I got some traction, but eventually I got stonewalled. I contacted the reseller I bought the product from, and they have shrugged their shoulders. I want this source code, so what are my options to obtain it?