It's a poor state of affairs when honest people need to learn far more than they ever wanted to, about crypto/drm/license key protocols,, just to read their own purchases on multiple dvics. When in the time that takes, your average pirate has downloaded an entire library and read most of it already
But once more into the breach... Recap please in great detail exactly how you made the purchases. I.e. from exactly what store, with what device, using what app, and with what account... let's see if the resulting debacle can be flowcharted and puzzzled out.
Or, Google does give refunds for most digital hings if you have not used them. So as you have yet to enjoy even one page of one book you could give up, ask for a refund, and go buy elsewhere ?