As a F-visa holder, you are exempt from counting days and treated as a nonresident for 2013-2017. When you switch to H-1B in February 2017, you become a resident from February 2017 and make yourself a dual-status alien. While you are a nonresident, you are exempt from paying FICA. You will start paying FICA after February. To claim a refund of the FICA you have paid, you should contact your employer. If you are unable to get a full refund from your employer, you can request the refund from the IRS by filing a Form 843. For more information, please see More Form 843
