I've been an AT&T customer for almost 3 years, and have been in good standing. I have all of the U-Verse services and was looking to end my service with Verizon Wireless and come to AT&T. I called in to customer service yesterday and was told that I need a security deposit of $500 per line! I paid a deposit upfront for Verizon of $400. I've had numerous friends that have left Verizon and came to AT&T and they didnt have to pay a deposit at all and initially they had to pay one for Verizon. I would think that they could go off of my previous billing history through my existing services (U-verse). If I am able to bundle everything I don't see why they couldn't pull billing info from my existing services. The deposit isnt the issue, If it was like $150 I'd be ok with it. But $500 per line? All I'm trying to do is get a phone, not a piece of the company.
The deposit is based on your credit. Your friends that switched to AT&T must not have had anything come up on their credit evaluation. The deposit is refunded back after 1 year of service with no non pay suspends, and will be fully refunded back as long as you dont have a late payment on the date of the refund.
Another thing is you might want to try stopping by a store and see if the store manager can override the deposit, I've heard of some people trying that and being succesfull.