Cannot receive SMS/MMS from non-AT&T customers

Some basic facts:

-Originally had Google Voice # (630-xxx-xxxx) routing to my non-AT&T phone (Google Pixel) (309-xxx-xxxx) and started to see slow and out-of-order texts a few days back from non-AT&T customers

-Assumed GV was the problem, ported the number to my device, completed successfully yesterday evening

-From that point on, I have yet to receive a text from a non-AT&T number. But I can text them, and I can send and receive texts just fine

-I have had this phone nearly a year, and been on AT&T for almost 3 years with this as my 3rd phone, all purchased elsewhere

-On latest stock factory Android (7.1.2), no 3rd party messaging apps could be intercepting, 4G/LTE/WiFi all work fine

-Already cleared out app cache and tried some other steps w/Google Pixel support

-Already opened a ticket with AT&T online support last night, and spoke with: Customer service (+2 levels of escalation), mobility advanced solutions, tech support, attempted to Tweet @ATT and @ATTCares with no response over 4 hrs later

-Person who opened the ticket indicated it was marked "critical and escalated", but that I may not hear anything until Friday afternoon. Meanwhile, I cannot receive texts from 85 - 90% of my contacts, including a mix of personal and professional people and includes my own father

Who can help me push this through to resolution more quickly, and truly own the situation?