I recently purchased a GPS tracker a G 204 for my car. All is working except I cannot get the GPS Tracker to communicate with my cell phone. The instructions say it must be a SIM compatible with either 2, 2.5, 2.75 G. My phone has a 3G. Can I purchase a 2G sim card? or is there another answer which someone may have come across previously why this may not be communicating. I would appreciate any help.