Lawyer here. Pure speculation/not legal advice:

Theoretically, people who purchased complain to their state attorney general or report the manufacturers to the FTC. There might be some recompense under consumer fraud laws. If enough people had bought them, there might be enough people to form a class action (doubtful though).

The problem is that amount of $ involved here is just not something anyone is likely to get up in arms about. It's $5. Most people will just write it off and never think about it again. No lawyer would bother either unless there were 10,000s of consumers willing to come forward and complain.

Just one of those shitty situations. Caveat emptor.