To contact AT&T regarding email deliverability issues, use abuse_rbl@abuse-att.net for abuse reporting and delisting requests, although direct contact can be challenging. Key domains include att.net, bellsouth.net, sbcglobal.net and currently.com. Improving deliverability requires proper authentication (SPF, DKIM, DMARC), monitoring sender and IP reputation, actively managing bounce messages and feedback loops, and adhering to email sending best practices, recognizing AT&T's infrastructure ties to Yahoo/Verizon may influence filtering.