The camera lens has dust, which means that the inner seals are not good and should have come naturally by the hole of handset. I took it for service and they changed it with a new one.
As I got bored of waiting an update to Kitkat, I sold it and now I have a Sony Xperia, which received Kiktat the end of last year and this month receive Lolipop. It also influenced the radio is not stereo and did not have NFC.
End of story for me, I learned that if you're buying a Chinese phone, has to be something like a Xiaomi, Meizu, Huawei and Oppo, in that order, obtaining price, quality and secured updates.