Like most phone sometimes the software can become unresponsive. Just turn off the phone. take out the battery for a minute. Restart the phone and it should take a charge. if your phones battery doesnt come out you might need to perform a hard reset. this wipes your data so i reccomend backing up your data.

Hi jamie! Have you tried charging using a USB cable to a computer? Or a different USB cable? Also try charging using different wall sockets. The problem may be on one of those.