[general] Where can I listen to these audiobooks?

So I have a subscription to Audible and I really like it (not a sponsor) but I've recently been collecting Rick Riordan's books. After I collected a few I noticed that there are 2 books that are not available on audible, or at least in my region (Florida USA) I was curious as to what platform I could listen to the Kane Chronicles book 3 the serpents shadow, as well as the heroes of Olympus book 2 the son of Neptune. Or if they are available on Audible in a different region and I can just use a vpn to get them? Sorry if this is the wrong subreddit I'm new to reddit lol.