Get your taxes done using TurboTax

I thought I was divorced but apparently my exwife, Billyjean Gray is still using my social security number on her tax return.  All I want is the government issued money I’m owed of $600.  I put single on my return and it was rejected due to being claimed a spouse on another return filing separately.  How do I change my status to married filing separately so this $600 is no longer held up