The reason why the Do Not Call Registry and file a complaint system is not working might be because of a system shutdown that is probably caused by a technical hitch. You can try again later when the systems are up again.
Actually the "File a Complain" feature under the donotcall.gov site has not worked for the past 2 weeks at least. I've tried from 3 different locations, 2 PCs, and using both Firefox and Internet Explorer. So it doesn't seem to be a temporary server side glitch.
It looks like it's been disabled or it broke and the contractor that built it is charging too much to the FCC to fix it. Hopefully it comes back because it seemed to have worked with some annoying telemarketers.