回复：social security and medicare during OPT ?

I would like to share my experience with you.
(1) You can get your money back when you do your tax return. Find a good accountant who has experience in this field.
(2) It takes 3-5 monthes for IRS to handle this kind of case.
(3) It might be difficult to explain such complicated situation to your current employer, a samll company as you mentioned, because it is a very special field even people from IRS mess up the case sometimes.

Good luck!