I have a Samsung Galaxy S duos S7562 dual sim mobile phone. Off late i am facing one peculiar problem. In my office, i am not able to make or receive any call through SIM1(BSNL SIM)(It shows the message call ended after calling any number), where as i can make normal call through SIM2(Airtel SIM). The network of SIM 1 is OK. When i go outside of my office or from any other place,i can make call through SIM1. But at the same time when i remove the SIM1 and put it on my old Nokia mobile, i am able to call and receive in my office also. Also my colleagues in the office are able to make call through the same Service provider as my SIM1 from the office itself. But i am not facing the problem in SIM2. I have tried to interchange the SIM1 with SIM2 also, but no improvements found. What could be the problem. Kindly suggest some solution as my SIM1 is my main no. and most of the time i spend in office