Autopay Change is False Advertising

When I signed up for the service I got a discount for autopay if I provided direct bill to my credit card.  Now T-Mobile changed that.  The commercial says no surprises, no increases, no fine print, no yada, yada, yada. Well, surprise, surprise, surprise, the fine print allows them to change that to just a debit card or direct access to my bank account. Now my monthly bill is 10% more.  That's false advertising.  That's the definition of yada, yada, yada.  That's wrong.  If they want to make a change, do it prospectively and grandfather everyone who was already covered.  I can't believe that some lawyer hasn't jumped on this for class action certification.  I would join that class in an instant.