毕业后在学校以opt身份做了4个月postdoc，f1超过5年。发信给payroll想要要会ssn
和 medicare tax。得到如下回信。请问我该如何回复能要回来？还是直接找IRS要？
You have been in the U.S, for more than 5 calendar years under F-1 visa. You
are a resident alien for tax purposes. When you worked under OPT with an
employment Authorization card after graduation and not registered as a full-
time student, you are subject to pay Social Security and Medicare taxes.
Resident aliens are taxed the same as US citizens.
谢谢！
