Switched from AT&T and bill is a lot more than I was quoted

I have a similar issue, I switched from AT&T and got 3 phones and 4 lines. Was quoted and have a screen grab for 202/month which included a bogo and 2 device trade ins. Now I'm 5 months in and notice my bills are 235, so I call and expect to have a resolution. Nope. They investigated for 48 hours and decided no they would not honor the price they quoted because I can't combine promos (there were only 3 promos for 4 lines, no combo!) and they would not return the trade in device and I am obligated to either pay off the phones completely if I want to cancel!!! If they'd have contacted me proactively about the misquote I could  have decided and may have stayed given it was still cheaper - but the utter lack of responsibility is astounding. In what other industry can you say "sign up now for X" and then get away with "it's really X+++ and yiu have to keep paying that for 3 years or else pay $$$$ to get out of contract early"

I thought it couldn’t get worse than AT&T, but T-Mobile proved me wrong in both customer service AND mobile coverage quality!!