I totally understand the frustration of an expen$ive mistake.

Even if you can't return them, there are still people who are willing to buy very lightly used cycling shorts. I wouldn't buy something that someone's sweated into for years, but I'd totally consider buying shorts that were used once or twice and then laundered. Of course, you will have to seriously discount it (at least 50% off) but that's better than losing all of the money you paid for it.