I don't have a 602, but it does sound like a hardware/firmware issue as fj says. I have had contact with pocketbook Customer Service (once when I called, I actually spoke with the CEO for North America) and they are fantastic. I'm sure they will help you figure out what exactly is wrong and how to take care of it.
Here are some customer service contacts:
email:
service@pocketbook-usa.com
phone: 816-510-1317 (if you are in the Kansas City area)
877-326-0196 option 2 (if you are not)