hello i have recently restord an iphone 3gs but n longer have at&t and i threw out my old sim months ago. my iphone is stuck on the activation screen and i have a blank tmobile sim card and an activated tmobile sim card. when i put the activated tmobile sim in it says new voicemail and dosent let me do anything. my blank one dosent do anything. i need to do this from my computer at home and i cant go to the store to get any sims from at&t or apple store or whatever