I was using my phone awhile ago while I was in my aunt's house. I forgot to bring my charger and so my phone drained all its battery supply. My phone was off for about 2 hours and by the time I got home and managed to charged it for a couple of minutes, what I first noticed when I turned on my phone was that there's no service on my sim. I have no idea what happened or what is the problem. I tried to click on the error and choose the "automatically connect on the preferred signal or network" (I forgot the actual text). Now, I can't seem to receive calls or texts and I can't also send them out as well. It's as if I don't have a sim inserted on my phone. I was sure that I didn't drop my phone or did anything which may trigger such errors. Please help me out on this one.