Definition of mandible. 1  1a : jaw 1a; especially : a lower jaw consisting of a single bone or of completely fused bonesb : the lower jaw with its investing soft partsc : either the upper or lower segment of the bill of a bird.
Using other AT&T Payment Options. 1  1. Pay your bill via the automated phone system. Dial 1-800-288-2020 to access the 24 hour-a-day telephone customer service system. 2  2. Speak with a customer service representative. Once you have verified your phone number, the phone system will ask you what you would like to do.
Submitting Complaints. Submit complaint to AT&T. Reach customer service by calling (800) 331-0500. Submit a complaint letter to AT&T Headquarters, AT&T Inc., 175 E. Houston St., San Antonio, TX 78205.Also submit a complaint letter to the wireless division at AT&T Mobility, 5565 Glenridge Connector, Atlanta, GA 30342; send a copy to its fax at (866) 783-9099.ubmitting Complaints. Submit complaint to AT&T. Reach customer service by calling (800) 331-0500. Submit a complaint letter to AT&T Headquarters, AT&T Inc., 175 E. Houston St., San Antonio, TX 78205.