when you say it does not work, is that voice/text/data or all three? I assume you have activated sim and it has credit. if data you may need to manually enter correct APN details etc to the correct sim port. your carrier will have more info on settings. I recently added a second SIM card on my device. I have to send a text, it then sends a reply and my phone gets updated. this did not activate until I reboot my device.