Exact same thing happened to me on a grandfathered text/mms plan. I was told the exact same thing, but kept going up the chain of command until I spoke with someone in the office of the president. Miraculously, the plan was able to be added back on after being told countless times it was a lost cause....I made them add a written note on my account saying nothing whatsoever could be changed without written or faxed correspondence.
Every single time I would go into the AT&T store for something as simple as purchasing a phone charger, the rep would ask for my number. I found this odd but obliged anyways. I found out later that AT&T reps were payed commission for every 'feature' that they up-sold to the customer. So, you will have unscrupulous reps adding on redundant features just to get a commission. What they would do as to hopefully not alert the customer was remove your add-on txt plan for instance, and add it right back. In my case the idiot removed it, only to add back the current 'mediamax' plan which wasn't nearly as nice as my grandfathered plan.
Why AT&T didn't have a more through checks and balances system was beyond me. They were probably getting scammed out of millions on commissions by employees. Maybe they've done something since then as this was years ago..
Just last year when purchasing a couple iPhone 3GS, and telling the rep that I just wanted the phones and not a single solitary thing changed on the account; I get home to see she has not only removed my family text messaging and added the $20 unlimited package to each line, but also marked 2 phones that didn't even get new iPhones as having done so, thus my upgrade dates were screwed up. I made sure her manager became aware of this, and he handled the situation, although not promptly.
Moral of the story: Never go to an AT&T store if you don't have to. I'm pre-ordering this year. Also never give them your phone # when purchasing accessories, as this is a window into your account. I know there are good people working there as well, but I've been burned by them so many times I avoid the stores/customer service like the plague! I actually went in a few months ago and made them give me a print out of all the upgrade dates for each line on my account, and had the store manager initial it. Taking no chances.
