Just received the following email from ATT:
Dear Valued Customer,
We hope you are enjoying your iPhone! We appreciate and value your business but need to alert you to an important issue with your account.
As an iPhone customer, an eligible data plan is required as part of your service agreement. There are iPhone(s) on your account that do not currently include this necessary plan. To ensure you have the best possible experience with unlimited data usage in the United States, please help us update your service.
To add the required iPhone data plan, simply dial 611 from your iPhone or call our Customer Care team directly at 1-800-331-0500.
It is important that we hear from you no later than September 14 to avoid an interruption in your data service. Your voice and SMS services will continue to work; however without data services, you will not be able to email, surf the Web or receive Visual Voicemail. We very much want you to enjoy all the revolutionary features of iPhone so please contact us right away.
For more information about iPhone voice and data plans, please click here.
Thank you for being an AT&T customer. We look forward to continuing to provide you with a great iPhone experience.
I am not sure what the best course of action is yet, but I am thinking about just swapping out my sim and using an older phone for a few days or maybe a week so the system registers the old phone... maybe that will work?