I had an extra GB of data added on during a Christmas promotion last year. I just upgraded my phone and now that extra GB is gone. I explicitly stated when I got the new phone that I did not want my plan to change. How do I get that back?
You had an expired plan, no doubt and this will be a problem. Call customer service and ask to escalate the call to a supervisor. When making any change that may have been the trigger to end your plan. Perhaps an agent made a move that failed to grandfather your plan.