Your controller could definitely be defective. Mine is having issues as well. Every one in a while I will get a mesage telling me to turn on my controller. I know for a fact that it isn't the batteries. I'm thinking about calling Microsoft to see if I can get a replacement. Doesn't the warranty cover the controller?
Yeah, the warranty covers the controller, I'm glad the Microsoft store was gracious enough to take care of the problem then and there, instead of me having to send the controller out to a repair center and then waiting for them to send me a replacement.