Email to SMS Problems

The issue is with T-Mobile and not Barracuda Networks.  I own a text marketing company that sends over 500,000 messages per day in which 100,000 alone are to T-Mobile subscribers. Forcing MMS by creating a message longer than 160, setting the content type to "html/plain" or even including an image will only prevent T-Mobile from "repackaging" your message to a temp short-code for delivery. This will not stop the 550 permanent error. Even if you have the correct SPF, DKIM, PTR (rDNS), SMTP Banner and any extra SMTP IP A records set to your mail server, the failure will continue. What is happening is T-Mobile's SPAM filter (not Barracuda) is seeing your messages as SPAM, if you are using the same subject every time and delivering to just 100 @tmomail.net.net subscribers every 24 hours, you can be blocked permanently.  We resolved our issue by purchasing another TLD (domain) and sending mail through that channel. It was actually a good move because all of our clients access the platform/website through "example.com" but all the mail is delivered through "example-mail.com" but both domains have the same hostname/mail server name of mail.example.com. Hope this helps anyone who has had issues. Remember to use MXToolBox or DNS Stuff to check your IPs, mail server, domain, blacklist, SPF, DKIM, PTR and other records for accuracy.  For those sending a lot of messages per day it's advised you use round-robin IP sending if you have more than 1 IP on your server as well as configuring EXIM in all areas on your server both GUI and command.