Have you peeked inside to see kind of battery it has and the volts and milliamp ratings listed on it....Just maybe a new battery would revive it....Plus have you checked to see if the charger has output volts ?
The P2V+ remote and wifi extender both use a micro USB type B connector for charging. If your cable charges the RC and not the extender then you likely have a bad battery. Does the extender power on with the charger connected? If not then it may have other issues.