My Brest Friend

So my biggest regret purchase was the my Brest friend pillow.  I used it literally one time and found it so awkward and uncomfortable. Maybe it is because I'm short waisted. I find leaning back in a comfy chair and just using a regular pillow works for me. Anyways, I can't return it because I threw away the packaging (dumb me). Any suggestions for how to go about selling it?  It's a shame to throw $40 down the drain.