Get your taxes done using TurboTax

I have a negative AGI and the "get payment" tool on the irs website won't accept a "-" symbol when I enter the number. I get locked out for 24 hours after entering the "wrong" information once. I'm at wits end. Anybody know what to enter for AGI in this case? I'm filing a 1040 and entering (trying to) line 8b. Thanks in advance