While I was on F1 Visa, my employer witheld social security and medicare taxes for me in error, and has declined to process a refund. IRS has a form 843, which allows you to petition IRS for a refund of this nature. The form says that you may properly request for a refund in a certain amount of time. Here is what it says:
Generally, you must file a claim for a credit or refund within 3 years from the date you filed your original return or 2 years from the date you paid the tax, whichever is later
Can someone please explain me the meaning of this? What is meant by "original return" here? and what is considered to be the date I "paid the tax"?
Suppose my employer wrongly withheld my taxes in year 2013, all year. How long do I have to ask for a refund in this case?