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.
Note the ATT Customer Service Number, or look for a specific one here. Main ATT phone number: 1-800-331-0500 or 611 from your wireless phone. ATT Customer Service Hours: