if they change the contract during the term of the contract (usually 2 years) you will have an option to cancel if you do so within 30 days of the change. That's the usual language these days. However, most US cellular carriers are moving to contract free plans. You just are obligated to pay off your phone, either all at once or through payments. 2-year contracts are almost a thing of the past.

About your friend getting a free phone every upgrade, period or face a class action suit - good luck with that. Sounds like they don't know what they are talking about.