Remember the tmobile un-contract? This is literally from their press release in 2017: "T-Mobile ONE customers keep their price until THEY decide to change it. T-Mobile will never change the price you pay for your T-Mobile ONE plan. When you sign up for T-Mobile ONE, only YOU have the power to change the price you pay." https://www.t-mobile.com/news/press/un-carrier-next
Remember how they promised the FTC they wouldn't raise prices if they could pretty please merge with sprint to become the biggest telecom network in the country? https://www.yahoo.com/news/t-mobile-promises-sprint-merger-195428217.html