Hi pjones,
Have you already checked your PDA to see what the tracking device (pill) looks like?
If the pill has already self-destructed (you should have noticed a tiny puff of smoke), then the search will move to another location and you have to start over.
Check your PDA messages for the next location.
I'd recommend saving your game just prior to moving to the new location, so that if you're unable to find the pill in time, you can reload and search in a different area of the scene.

You won't be able to sell back any item you've bought by mistake.
