Hi,Got a an iPhone 4 on 29th Dec.. My nano sim wasn't compatible so went to my network provider Airtel and got a micro Sim.. The executive said the sim will be activated in 4hrs.. But still it's not activated. When I call the customer care they say the sim is active and they have nothing more to do from their side..I tried another friends sim in my phone which works perfectly.. But my sim doesn't work in his phone. Tried resetting the network. Removed the sim and replaced. Turned off and on the airplane mode.. But no network in my mobile. Tried restoring the iPhone with iTunes.. Nothing worked. can anyone help me please..