Hi there,
it may be possible that your car does not allow music playback over bluetooth. I have a similar situation with Skoda Octavia.
I used the same phone or different phones in a Citroen Berlingo and plays everything.
This means it depends of the car as well. You can check if the media playback is marked in the settings of your bluetooth connection. Try finding it in both car and phone.
Over the USB to aux, I don't think you can play music.
You should be able to play over cable if you have an AUX-in to your car, and just use an audio cable.
Hope that helps.