I actually work at SiriusXM, so I can answer some of these questions. Feel free to message me, too.
Every FPACE that has SXM as part of the spec comes with a free three-month trial. Your dealer SHOULD have activated the trial for you before left the lot, but most dealers don't do it. So, you can call either the number that comes up on the screen when you go to it on ICT/ICT Pro or call 1-855-599-5618 to activate your trial. No credit card or anything is required.
If you picked up your FPACE in the last two weeks, you were able to listen to SOME channels for free (60 of them). That's our Free Listening program (which I run) and it's a way to get former listeners to check us out again and hopefully resubscribe. Your dealer might have thought your trial was active, but it's a completely different program and doesn't affect your trial.
As for reception - yes, if you're in a place where access to the satellites is blocked (tall buildings, tunnels, mountain passes, etc), it will cut out for a few seconds and then come back.
I think
@Jagfirst's issue is with the system itself.