They may be tweaking the towers. Does your area have LTE? they may be making changes to support the LTE rollout or other upgrades. Call att and ask them to check out the network/towers in your area.
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For service or support questions including existing order status, call:
Customer Support: 1-800-331-0500
Information on iPhone unlocking can be found here by copying this link into your browser:
https://www.att.com/deviceunlock/client/en_US/
