[Plextalk] PlexTalk Pocket won't charge the battery

My PlexTalk Pocket will no longer charge its battery either through the AC adapter or via the computer. I tried updating the firmware to the latest version which I thought was supposed to eleviate this problem, but my PTP won’t update even though it downloads the sample books that come with the update. Any suggestions for fixing this problem would be much appreciated. Blessings, Naomi in Michigan