Are you paying for Verizon Cloud? The free version only allow contacts to be saved. Since you have apixel why not use Google Drive or Google One
Yes, I have the 500 GB plan. If this is a proprietary issue on the Audiobook side, it may not matter which cloud that I use. Does Amazon have a publicly available cloud for Prime members? Since Audiobook is an Amazon product, maybe audiobooks can be stored on its cloud?
We want you to have the support and guidance needed. Since Audiobooks is an Amazon product, we recommend as your next best step, you reach out to Amazon directly. I hope this is beneficial.