Initial Activation : 4000 US Reseller Flex Policy Applied Activation : 23 US AT&T Activation Policy Next Tether : 23 US AT&T Activation Policy
Those imeis are the one who will not get unlocked using clean service or premium service but you know they are AT&T. Some common error is "The IMEI you entered does not appear to be an AT&T wireless phone or tablet." when using AT&T Clean Service.
This is a special service for those imei, but you must first run a GSX Checeek report and make sure it show: "4000 US Reseller Flex" for initial activation And the device must be activated first with an AT&T SIM Card.
DO NOT SUBMIT, TMOBILE, TRACFONE OR NOT ACTIVATED ETC. THIS SERVICE ONLY SUPPORT DEVICES ACTIVATED WITH AT&T NO LOST/STOLEN DEVICES, OR FRAUD DEVICES
Service works ONLY on working days. Weekends and holidays are not included.