I was on F-1 from Jan-2017 to Sept-2017, My status for H1 changed from OCT-2017.

My employed deducted FICA taxes from the paycheck which had been paid in the first week of October but it had the pay period from 15 Sept to 30 Sept. I contacted my employer payroll department and they said:

"You were converted to H1B effective 10/1/17 and therefore will now pay social security and Medicare taxes going forward. Per the IRS guidelines, any payments received on and after 10/1 will be applicable to FICA taxes"

Actually, I got paid for the last two weeks of Sept 2017 in the OCT first week. Does it matter the pay date? Technically, I paid the FICA when I was on F-1 Visa status Is there any way to get back deducted FICA?