The discount is only for "high data usage" customers only (those who sign up for 15GB or more data per month). There are planty of Mobile Share customers who are complaining that they aren't getting the promotion either. If you're on an Individual plan and have enough data charges to qualify for the "double data" promotion, then you should really look at the Mobiel Share plans. I'm thinking that a 15GB Mobile Share plan for one user at $170/month (contract pricing, lower if you are out of contract or use NEXT to buy your phone) giving unlimited talk & text would be cheaper than your individual plan with 5GB data for $50 + 10GB more at $10/GB plus your minutes and texting plans, and then you would qualify for the "double data" promotion as well.
BTW, if you are still on an older "individual plan" then you are on an old "grandfathered" plan. Your plan does not include any discounts for your service if you are not under contract, so your monthly service charges always include an amount to re-pay AT&T for the subsidy on your cell phone. The newer Mobile Share plans giv you discounts when you are not under a service contract, and can save you some money in the long run. It can save even more if you have multiple phones on you plan.
BTW, if you are still on an older "individual plan" then you are on an old "grandfathered" plan. Your plan does not include any discounts for your service if you are not under contract, so your monthly service charges always include an amount to re-pay AT&T for the subsidy on your cell phone. The newer Mobile Share plans giv you discounts when you are not under a service contract, and can save you some money in the long run. It can save even more if you have multiple phones on you plan.