I agree with @juanmanuelfangioii, save your money. The main problem is that you're not using the MiND app to access and playback your music over the 780D. You'll probably need to set up file sharing on the PC that has your music library. Then the MiND app can access, index, and stream those files directly to the DAC.
I took a look at the 780D manual and it mentions none of this. Did you buy from a dealer? They should've helped set this up for you.