I am not able to use Spotify Premium acct as a library source on DJ 2 app for iPad 4

I purchased the DJ 2 app from the Apple app store today. Installed this onto my iPad 4 and went into settings and tried to use my Spotify Premium account. No go. In settings and under library only thing listed is iTunes Store. Choose USA and then after backing out of that setting I say Spotify but a box is showing me Log out of Spotify. I did log out of Spotify, no change. I use Facebook to get into Spotify, tried going into Facebook, remove te Spotify app, even reset my password on Facebook and logged into Facebook using my new password but still, your app simply does not do what is advertised. I bought this app simply for Spotify to be used for my library. Spotify will not let me log in any other way than Facebook. Please help me chance my opinion on your software and support.