Please try the following steps to see if this helps resolve your issue
1. Plug the USB charger cable to the device.
2. Press hold the power button for 60 seconds.
3. Let go of the power button and let the device stay plugged in for about 10 minutes and wait for the charge to start.
Repeat step 1-3 a second time if this doesn't jump start your Pocketalk.
The following video may also help illustrate these steps better for you.