I wrote to Ted Cruz on Jan. 14th, 2015 and I received a response from him in the mail yesterday. I don't know if it is authentic or not but I'm super excited!
I emailed him but he emailed me an automatic reply. That was a couple weeks ago! I really want his autograph. I live in Illinois so maybe he only sends to certain areas.
I wrote to him through his website: http://www.cruz.senate.gov/?p=email_senator and requested an autograph. It was a quick turn around maybe 2 weeks from the time that I wrote to him. Good luck! I too, live in Illinois.