This article describes what to do if you cannot connect to a 3G MicroCell.
INSTRUCTIONS & INFO
Add the phone number associated with your Wireless Home Phone device to the MicroCell's approved user list.
Powercycle your MicroCell; unplug it from the wall outlet, wait 30 seconds, then plug it back in. Powercycle your Wireless Home Phone device; turn the On/Off switch to Off and then back On again.
Make sure the Wireless Home Phone device is within range of your MicroCell.