Streaming Channels on Car Radio

Channel list shows Classic Rock Top 1000 (553) as a streaming-only channel.
However, it was available on one of my new car radios and was set as a preset channel. After performing refresh on radio signal to correct the plans on both cars (they were reversed .. one had Music Showcase plan, while the other had Platinum trial). Refreshed the signal for both per customer support. Now channel 553 is not available at all. It is weird that it was on the radio to begin with. Not sure how that could've happened. I have iPhone connected to the one that was able to play 553, but it was there without the iPhone connected. Anyone have this happen or any ideas how this could have occurred?