Tmobile trade in is SCAM

I've been a T-Mobile customer for 17 years. I was on the Magenta 55 plan paying $70/ mo for two lines. I attempted to upgrade my iPhone XR to an iPhone 14 on the T-mobile website. I got a trade in estimate for $400, but when I tried to checkout the trade in credit did not show up in the total. I called T-Mobile customer service. They said I needed to go into a T-Mobile store to get the full trade in value. I went to a T-Mobile store and spoke to a "Mobile Expert." He told me that their best deal was an $800 trade in for my iPhone XR, but I needed to upgrade to the Go5G plan which would be $100/mo, a $30 per month increase. Though Go5G was $720 more over 24 months, he said I would be able to get the $800 credit for each line. Based on his explanation, that's a $1600 trade in credit for two phones for an additional monthly fee of $720 over 24 months. I agreed to the deal. After committing to sign a 24 month commitment to upgrade my plan to Go5G, they only gave me a $270 credit instead of $800 for the trade in. It was a bait and switch to get me to upgrade.  Now, like many other T-Mobile customers, I'm screwed and they won't do anything about it.