Why is the audible app no longer compatible with my iPod touch 5th generation

I used to listen to books on the audible app. On my touch 5 gen. Now I go to listen to a book and no newer books were in my library and it would not refresh. I called audible and the had me delete the app and re download it but I could down load because it said it was no longer compatible with this device. Apple had me sign into audible. com through safari and it did show all my library but when I hit play it buffers the said it can’t play it. What’s going on? How am I going to listen to my books? That’s the only reason I even bought it