I think that I uploaded 13 songs while in Ubuntu this afternoon. When I opened the app on the iPad, it said I need to subscribe to the streaming music service. I did. I entered my account information but I still can't find the songs. What else should I do?
The streaming service relies on metadata scanned from songs found in your personal storage (so you can pick songs based on e.g. artist rather than what folder you put them in). This metadata scan is only performed for people who have subscribed to the streaming service, so it may just be the case that your songs haven't been scanned yet.
If the problem doesn't correct itself in a few hours, I would suggest using the contact form so the problem can be investigated and you can make use of the service you've paid for: