My problem sounds like this:
I live in a country which does not support OneDrive integration into Xbox Music. So I changed the region of my microsoft account to US in order to be able to use this service. The idea is that the Xbox Music Web Player is working now and is reading my songs from the OneDrive (Before changing the region i could not use the player. It was saying that the region is not supported.). But the Xbox Music app from my Windows Phone 8.1 set to United States is not showing the mp3s from my music folder from OneDrive.