XM Radio keeps reverting back to Channel 0

I recently purchased a Prius. I had Sirius set me up with a trial membership and send a signal a number of time to my radio, but it keeps resetting to zero. I've tried turning the radio on off--the "tech support" at Sirius told to take car to an audio shop to check it. I frankly do not think it could be a problem with the radio--everything works on all other channels and channel 1 works with the previews. I don't know what an audio person could possibly do--I think the issue has to be with Sirius. Any ideas?

 

Interestingly, I had sent a re-set signal at home (I originally had tried at work) and it worked. Both places I was outside in clear view of sky--perhaps something near where I was interfered with the signal. You would think one of the "tech" people would have told me to try moving my car to a another area and see if that works!