Yes, federally you're required to see someone's ss card upon hiring.
I would also contact the SSA....and let them know your SS number has been used fraudulently.
I would check on line and see if any type of credit had been extended using your SS #. It's free.
https://www.annualcreditreport.com/cra/index.jsp
Hopefully this is your only issue and they haven't gotten credit using it. That is a nightmare....they open the accounts but never pay the bills...and THAT is what ruins your credit.