Automatically added data plan??

Ok so here's the deal, I recently added a line for my unemployed sister so she could have a phone to help in her job search. When I added the line I got some free phone that didn't require data. Well she has a HTC Inspire that she used to use as a go phone. Once I saw that data was on the line last month I called AT&T and removed it by giving them the IMEI of the free hone and asked them to put the data block on. They did. Now I'm getting an email saying they added the $30 plan to my account. Is there any way whatsoever I can get around this? Esp.. Since the phone was originally purchased and used for their prepaid service? I thought the data plan was only a requirement because you get the phone at a cheaper price when buy/upgrading.

I'm just asking because I'm already footing most of the bill for the 4 lines on my account but I refuse to pay for data on her phone when she can use the wifi in the house...