20 Most Recent Plantronics Voyager PRO Bluetooth Headset - Page 8 Questions & Answers

If it will not hold a charge then the battery pack is worn out/defective and you must replace it. You can find the number on the battery and get them on eBay.

Ive only ever seen this caused by using wifi calling make sure your calling from data plan and not wifi network. I had to disable wifi calling .

Sorry to hear about your bad luck there. If a hard reset does not work and its not simply the power button is not correctly aligned (try fiddling the pressure up and down if it is loose) then it's likely the device has failed. Even though it's survived other power outages it's still entirely possible the most recent one has caused this failure. I've seen failure of electronics from operating on unstable voltages from solar panels and less than perfect inverter systems and it's always the case that "it's been working fine up until now!"