Won't lie the mix needs sorting out a bit BUT a mix down doesn't make a good song but bare it in mind for your next song!
I think the synth cuts out on second drop because a filter (Might be a lowpass) on the synth goes so low that it just blends with the kick. So yea have a look at that LFO you think it is :P.
The choppy vocals that you've tried out are a pretty damn good attempt and is quite melodically pleasing. I'd say possible add a bit of pingpong delay and reverb to fill out the mix a bit more!
Good stuff mate soldier on :)