UPDATE: I have tried with another charger, which is supposed to be fast and also support the MTK PumpExpress Plus. The adapter is the Sony "UCH 12" and operates at three different voltages, 5, 9, 12. But I have the same problem as with the other chargers. The red LED goes on but the phone doesn't charge. After 40 minutes it is still 0%.
Funny enough, the phone charges (slowly) when I plug it to the usb port of my laptop... Isn't that weird?
If someone could give me an explanation for this before I buy other adapters, I would really appreciate that. Thanks a lot!
Just for information... what's your firmware version?