[Resolved]  Airtel — Sim is not being detected

Hi.
My number is [protected].Many a times my cell is automatically getting switched on and off and then it says.."Invalid Sim" "Simcard Not detected" I've ensured about this problem not being related to cell as I've checked the sim in other mobiles. Also,when i insert this sim card on other cells,I can't see any of the contacts which were stored earlier on the sim card.Tell me what to do now.Is it possible to get a same number sim card which works fine ?