Not getting texts from certain number

Okay, so I'm not receiving authentication texts from a certain number/system that worked to yesterday.  I've been on phone chat and am told that "Xfinity doesn't block" any calls or text, which we know is BS.  I need to figure out how to resolve this soon else I need to switch providers so I can get these texts.  Job and all that. 

Edit: To clarify the app vendor ran a test to see if any text would come from their systems to my number and there no result.  As such, it most definitely appears to be an Xfinity problem.