No service after flight mode switched on and off

Hi,

I switched the flight mode on for the night and switched it off in the morning and after that I've not been able to get service on my 4S. I tried restarting many times, resetting the network, tried putting the sim in a different phone and it worked fine. I haven't dropped the 4S or anything, it worked perfectly the evening before and the next morning it was an iPod and even though I am in wifi, I can't even receive iMessages on it. Apps such as WhatsApp, Viber, etc do work though.