iPhone text message to Cox e-mail not working

I have been calling and calling Cox to get this fixed.  They assigned an ticket number CUI000007461929.   But no one at upper level tech support will even look at the ticket.   No one can send text message from an ATT phone to a Cox.net email address.  It is not IPHONE only.  It is any phone. I have had the tech on the phone confirm it with their on ATT phone.  This is a network wide problem not limited to one user or one type of phone.   NO ONE seems to want to fix the issue.   you can send from your ATT phone to Gmail, etc just fine.  Cox is the problem.  You can send from MetroPCS, USCelluar, and others to Cox.net, just not from ATT.