You guys won't like this answer very much, however this is from your AT&T contract:
1.3 Can AT&T Change My Terms And Rates?
We may change any terms, conditions, rates, fees, expenses, or charges regarding your Services at any time. We will provide you with notice of material changes (other than changes to governmental fees, proportional charges for governmental mandates, roaming rates or administrative charges) either in your monthly bill or separately. You understand and agree that State and Federal Universal Service Fees and other governmentally imposed fees, whether or not assessed directly upon you, may be increased based upon the government's or our calculations.
IF WE INCREASE THE PRICE OF ANY OF THE SERVICES TO WHICH YOU SUBSCRIBE, BEYOND THE LIMITS SET FORTH IN YOUR CUSTOMER SERVICE SUMMARY, OR IF WE MATERIALLY DECREASE THE GEOGRAPHICAL AREA IN WHICH YOUR AIRTIME RATE APPLIES (OTHER THAN A TEMPORARY DECREASE FOR REPAIRS OR MAINTENANCE), WE'LL DISCLOSE THE CHANGE AT LEAST ONE BILLING CYCLE IN ADVANCE (EITHER THROUGH A NOTICE WITH YOUR BILL, A TEXT MESSAGE TO YOUR DEVICE, OR OTHERWISE), AND YOU MAY TERMINATE THIS AGREEMENT WITHOUT PAYING AN EARLY TERMINATION FEE OR RETURNING OR PAYING FOR ANY PROMOTIONAL ITEMS, PROVIDED YOUR NOTICE OF TERMINATION IS DELIVERED TO US WITHIN THIRTY (30) DAYS AFTER THE FIRST BILL REFLECTING THE CHANGE.
If you lose your eligibility for a particular rate plan, we may change your rate plan to one for which you qualify.