My SIM card is not seeming to work..
Please perform a factory reset on the device by doing the following:
1. Remove the SIM card from the device, and perform a factory reset (instructions below).
2. Look on the device, there should be a small button you'll need to insert something into, similar to the likes of a paper clip.
3. Press and hold the button for 30 seconds, and place the SIM card into the device. Now reboot the device.
4. Once the device is back on, for setting the APN settings, if there is an option for AT&T, please select it and allow it to propagate. If there is not, then use the APN settings provided to you in the initial setup email.