I found an easy solution to this problem with Google play music and power amp. I downloaded music mate to my phone and my Google play music showed up in music mate. But when I checked Poweramp it had not showed up yet. So I simply closed Poweramp, music mate and Google music app. When I reopened Poweramp all my missing Google play music was there. But music mate only moves 50 songs under the free version but I had less than that to move. I am thinking this is all you need to do. I found this solution on line over a year ago somewhere else. Hope this helps!