When I joined my plan a year ago, they asked me to put $300 deposit, and claimed that they would return it to me by VISA card. Now they did refund me, but only in my account, which means that I can only use the deposit to pay my AT&T. My friend has the same story. We're both really disappointed that the sales people lied.
I would recommend that you send a Private Message to ATTCustomerCare is part of the AT&T customer service team, They may be able to resolve your Issue. You can expect a reply via return PM between the hours of 7am-10pm CST within 2 to 3 business days.