So I just got this phone today from ebay and it doesn't come with the original charger , I have phew cables from my old lg and others phone which using the same port , the thing is when I try to charge it , I plugged in and the screen will not turn off , I tried to press the power button but a few seccond it turned itself back on, it just keep doing it and sometimes it even changed to dock mode and then disconnect even though it still plug in , HElP , what do I do now ?