Tbh I find it unlikely that both won’t, let alone neither arriving. My guess is now that USPS has your international one it’ll arrive quickly enough (depending on where you live in relation to the customs place) and that the one that’s misspent will probably arrive as well since they noticed the issue, it’ll just be delayed. Imo USPS is annoying and causes delays sometimes, but I’ve used USPS so so many times (including to send and receive international shipments) and I’ve had a few times where they were delayed or sent to the wrong place at first or whatnot but I’ve never not received a package. And the album store I use uses USPS, so that’s a crap ton of shipments

For receiving shipments I like some others better but mostly because I’m lazy and don’t like walking to my mailbox. But for shipping internationally I prefer USPS actually (though I haven’t done that often at all).