My girlfriend's mobile phone has power, but she doesn't know what she is doing and doesn't return my text messages.

I think I probably don't want to talk to you! Please try sending the message later. It is also possible that she is really busy and has no time to worry about you. There are many reasons. The man should be generous and ignore you. Don't be suspicious. Trust her, there are many things to do. So there may be a big reason why your girlfriend doesn't return your text messages.