Try to bend the charger when its in the phone. Not that it bends but its tilted a tittle in the phone.
My sister had the same problem with a iPod and it charged with this trick.
Try another charger
And if you can take out the battery and make sure the metal contacts are clean of dirt or debris.
If you still cant get it to work take it to a repair store that is trustworthy. Be aware this may take days to a week to fix.
But you can just get a new one.