samething happened to me...Ordered my iphone 6 at 3:20 am eastern received a confirmation sayong that my unlimited data plan was removed (the only reason why i stayed with at & t this long) i tried to call customer service right away but it was closed until 7 am. know ing that i wasnt going to sleep i put my alarm on for 6:50 am thinking id 1st call then go down to my local AT & T store.
called customer service at 7 got a representative at 7:15am. To my amazement after explaining my situation the lady understood where I was coming from and within 10 min i had a case and confirmation number texted to me and was assured that my unlmited plan would be returned!