A good number of people had battery problems with the EE. As far as I know they're under warranty for 1 year, so if it fails in this period I think enTourage replaces it (you can check with Tech Support).

Your indicated usage shouldn't have caused the battery to fail.

It is true that each time you "use" the device, you're using battery lifetime. However, by simply closing the eDGe when you're not using it (and/or turning off the wifi), you reduce the battery drain to minimal. You should get a good 8 hours of use on the EE if you're constantly using it, and 10-16 hours if you're using it on and off and closing it when not using it.