I was going to first comment, her vocals could use some eq added up top - but if she recorded it on a phone, that might be be problematic. Pretty good for a phone mic!
Your mixing is really nice here, especially the added vocal candy, and the reverb on the synth sax licks. Overall balance is ok - you might experiment with a master bus eq beefing up below 150hz? You don't want to add mud, though.
I admit though, while the mixing is solid, the parts themselves don't often really stay in the groove for long. There's always something complicated with the bass, the piano comes in unpredictably - it's a bit herky-jerky and I wanted it to groove more. There were plenty of measures where I couldn't tell really where the "1" was.
If you are going for a fragmented feel like that, then nevermind. Otherwise I'd crack that snare on 2 and 4 the whole time and run that sucker into the stanky ditch I hear for it. :)
cheers,
-Tom