I posted this way back in this thread (note to newbies: it is important to read all the way through a thread or you may miss valuable information) but as it appears many have not seen it, I'll repost it again here:
I had an interesting conversation with one of their Tier 3 techs... It seems that XM does not know from Adam about any of the free trials or radio IDs in new vehicle audio systems. It works like some OEM software licensing arrangements. Nissan (or whomever) gets a volume authorization and applies that to all their radios of a particular model. The date that the trial is to expire is hard coded in to the authorization and has no bearing on when it was actually authorized in the radio. He said that normally, a vehicle manufacturer gets a new block every month or so with a new date code in it so it isn't a big deal... Apparently Nissan's Leaf codes were somewhat "stale" and led to this problem. When the radio reaches the date code (the date is sent as part of the radio data stream), it simply deauthorizes. Thus, that is why when you call in, XM has no idea who you are and knows nothing about your specific radio: your radio ID has never hit the system since it all happens without any direct contact with them... For future reference, what they CAN do is, when you pick up your car give them a call right away and they can then create an account with your radio ID and create a 6 month trial for you from that point forward. If you wait a while it is apparently much harder for them to do this for reasons that could not be explained to me (probably marketing or fraud prevention).