I am having an issue regrding my nokia asha 306. Its just 3 months since I purchased this phone. Since the time of purchase till today it has been hanging and the icons either disappears or keeps space in between each grid. I has restored all my factory settings due to which my internet has stopped working and it keeps showing the dialogue "CERTIFICATE INVALID ACCORDING TO PHONE'S DATE." Kindly guide as to how shall I resolve this problem...