FICA is Social Security and Medicare taxes. You might see FICA withheld on your W-2 form (box 4 and 6). If you are a nonresident for tax purposes, on an exempt visa such as F or J visa, you generally should not be paying FICA. If FICA is withheld incorrectly, you would be entitled to a FICA refund.
You must first contact your employer(s) and request a refund directly from them. Give your employer(s) 1 month to respond to your request for FICA refund. If your employer(s) does not refund this to you, then you can proceed with the steps on Sprintax to generate your FICA tax claim to send to the Internal Revenue Service.