Can't Forward Text Messages - Used To Work

Interesting to say the least! You have done a ton of testing and troubleshooting already. I am curious how the test goes after switching the sim to the LG phone. I know you won't have the current messages, but since it happens on any forwarded message, you could have anyone send you a message and try to forward it to anyone else. If it is just on the Samsung devices, you can wipe the cache partition and check for updates. If the issue happens with the LG phone also, I would reach out to our care teams and get connected with tech support. They have a few other things to check for troubleshooting, but they can also file a ticket for the engineers to look at the actual journey of the message, find the exact spot where it fails, and then fix it. For the ticket, though, you want to have detailed examples of the issue within 48 hours before your conversation. Date and time (and timezone), phone numbers, length of the message, etc. Usually, you can tell the tech expert what steps you have already taken so they don't try to make you repeat anything you have already done. 

You didn't sound excited to call in to our tech support and I am sorry to hear that you don't think highly of that process. We do have other options, though. You can message us on Facebook, Twitter, or through the T-Mobile website or app. A lot of times, if you are on the website, there is a chat bubble that pops up at the bottom of the screen that can be extremely helpful, too. https://www.t-mobile.com/contact-us