Galaxy GT i9003 --- SIM contacts fail to show up

[amaktr]

My Samsung Galaxy GT i9003 was upgraded to gingerbread ever since it is not reading the contacts stored in the SIM card. Though on one occasion after getting the battery charged i switched it on the contacts from SIM card got restored. However another time after the recharge when i switched it on they disappeared yet again. I was wondering if there's some glitch in the gingerbread version and/or i should send my phone over to the service center?