Dude; the law of copyright is quite explicit unless you have a release from the creator of the track you cannot exploit it in any way shape or form.
I am not an attorney but I am a long time player in the music industry. I keep my head across all changes to copyright law proposed or enacted, no matter the jurisdiction, as it all affects me along the way.
Put simply, buy a lease to use the track and you're cool, use it without getting a lease and you could lose everything you own and whatever your future earnings might be in the worst case outcome should the creator/rights owner decide to pursue you.....