Welcome to the club. I loved my Aluratek, till I had that same issue. First time I charged it, I had almost 13 hours according to the battery indicator. After that, I couldn't get more than 7.
Sent it back at my expense, after numerous attempts to convince tech support that I was indeed shutting it down properly. After 3 weeks, I was told it stayed fully charged for them, so they sent it back. The first thing I did when I got it back was check the battery, and it showed just over 5 hours left.
Luckily, I bought the extended warranty. This allowed me to return it after the 1 year warranty ran out. I'm using a Kobo VOX now, but I really miss the Aluratek, as it did every thing I wanted an e-reader to do. I didn't need Wi-Fi, or any other bells n whistles.
But, I refuse to deal with tech support folks that try and play me for a fool.