My blackberry recently broke so i started using another phone with the same simcard. It worked and then my step dad gave me his old samsung gravity. I put the sim card in the gravity but it doesnt work.. Its not the sim card because it works on another samsung phone and the blackberry. The samsung works too because it turns on and everything the only problem is when its on a calling icon with a red slash accros it appears. What could be the problem and how do i fix it?