I think in this situation it would only make since to keep the bottle of wrong medication and maybe label it yourself on the top of the bottle I would have just written, Tylenol, and then maybe in red ALEVE so that your husband would not take it by mistake, put it up somewhere and let him know NOT to take that medication. You could have easily put it in a place to where noone would have seen it. But possibly you threw it out because you did not intend on them replacing it but just intended on cancelling your payment, although I would have still just sealed up the mistaken meds shipped them back to them and then stopped payment on my money order, if they wanted me to do that.
I do seriously doubt that JETSRX is going to start any type of criminal investigation regarding this nomatter what you do.

First of all, they are not about to draw that type of attn. to thereselves. There are too many people receiving the wrong medication and that right there would probably be brought out in any type of investigation which they would really not bother doing. So I think you should just either take the replacements and move on, or cancel the money order and move on. But either way, I would discountinue doing business with a company that does this on a regular basis!

There are two many really wonderful OP's out there that do not make these mistakes and are much cheaper for your money. Look into using someone like YOD in the future and avoid this next time.