When Apple announced its entry in the 5G era with its brand-new iPhone 12, telecommunication companies unleashed their offense to attract more clients. For switchers, T-Mobile (Nasdaq: TMUS US) is offering a bundle of two iPhone 12 Pros and two lines of service with its Essentials unlimited plan for $100 per month when trading in two "eligible devices". Those adding a line or switching but who don't want the Essentials deal can get "up to $850 off any new iPhone 12 series" so long as you are adding a line and trading in an "eligible device" in "good condition." Stocks closed 4% lower after the announcements.