Are you attempting to listen to a song, album or playlist on demand? If so, it sounds like you may be triggering an advertisement in order to initiate a complimentary session of Premium. You can find out more about how Premium Access sessions work in this helpful article.
If you're still having trouble, can you please send me a screenshot of exactly what you're seeing?
To take a screenshot on your Android device, press the Home button and the Power button (on the right side of your phone) at the same time. You may hear a camera shutter sound (if your volume is turned on), and your screen will be captured.
To access your screenshots, go to the Gallery and look in the Screenshots folder. In your next reply, click on the camera icon to attach a photo to your next post.