My at&t cell phone contract got shut off. I have an iphone 4 nd a samsung strive. I bought a $10 at&t gophone and was wanting to take the sim out of it and put it into the samsung. When i put it in and turn it on it says invalid sim. Whats the problem? I dont see why it would have to be unlocked since im still using at&t. But if it does need to be unlocked, will it still work when i put the old sim back in to continue on my contract?
Thanks!
Thanks!