Definition of derived. biology. : being, possessing, or marked by a character (as the large brain in humans) not present in the ancestral form derived features.
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.
AT&T phone numbers for existing customers. If youâre an existing customer searching for AT&T customer service or technical support, call 1-800-331-0500. AT&T experts will be able to answer questions regarding devices, billing and technical support, and order assistance.