I have the t-mobile Shadow pda phone and i have had it foe 3 days... the phone was brand new, and yesterday ..

the battery was running out really fast... it went from 100% to dead in less than an hr with out me even using it... i tried using a usb charger and it would say it was charging but the phone kept shutting off... i plugged it into the charger that came with the phone when i got home and it turned on and stayed on and charged up... now what i want to know is why other chargers wont work on the phone even though they are also from T-mobile and have the same usb connection?