I'm having problem with my Galaxy S3 unlocked. Messages are going quickly, sometimes taking time and rarely message not sent but I'm not receiving them quickly. It's taking too late to receive and rarely they are quickly received. Since carriers over here doesn't provide micro-sim so we have to cut out large sims and then ready to use. So, I did that but I also noticed that my friend who has S3 got smaller sim circuit and my sim's circuit covers almost whole sim. Maybe that could be the problem? Please answer so I can then contact carrier.