After you file

Hi, 

I checked the IRS website.  They show they deposited my stimulus check to my ex-husband (ex as of December 4, 2019).  I cannot find a way to contact them.  I had updated all of my employment and social security information before the end of the year.  I filed my 2019 tax return on April 6, 2020 by mail.  How can I get this straightened out?  My ex will not give me the money due to me.  

Thanks for your help!

Elaine