Text messaging issues

[AC Question]

For almost a week now I have been having strange issues with my sms and mms messages. I can not send a sms to a recipient that I have never texted before, I can not send or receive mms messages, and last and most strange, randomly, a few of the messages I am able to send are pulling up in old threads from contacts other than the original recipient, and it is changing the name on the top (who the thread is supposed to be going to) from the name; to the number of the person associated with the old thread it is now attached to. Any thoughts, ideas or help would be appreciated. I have already called my provider (att) they did some stuff remotely and it worked at a 80% solution while on with them, but now that I'm off, it is right back to the original statement above. Phone is a galaxy S6 Active.

 

[traymark]

Had the same problem a few months ago and having the same problem AGAIN! Specifically, I (using Verizon) can not send or receive text messages from my contacts that are on AT&T. The first time it happened I submitted a trouble ticket and it was resolved. Recently, it has happened AGAIN! Tech support told me the first time was due to my phone being blocked by the contracting company AT&T uses to transfer the text messages. Why the heck would they block my number? No one knows. Same problem has occurred but this time...although Verizon has texted me that my issue has been resolved. It was and is not. Something weird is going on and neither Verizon, nor AT&T are fessing up.