Yeo Birkhe.. u only pay Fed and state taxes when u r on F1/ OPT .. if u have H1B/ GC / PR then u have to pay SS and Medcare... even if they have taken SS and Medcare .. u can see this in ur w-2.. u can claim it back.. it usally takes about 6 months but u will get that back.. its worth trying coz it would atleast be around 600 if u worked fulltime.. let me know if u have any questions..