I bought used iphone(off eBay) and was using it under AT&T. I activated the data plan for 2 months(since I was going out of town). When I tried removing data plan, they said that iPhones or any smart phone should have a data plan. So I gave them a IMEI number from an old cellphone to replace the iPhone IMEI number, finally they removed the data plan. Now they warned that, if I use the iPhone again, the data plan will get automatically reactivated. Is this true? Just to be clear, I did not get the iPhone under AT&T contract.