Rule of thumb:
Never give any information to any link that directly asks your personal information. Always go with proper website.
I tried IRS web to verify something, I did not find to verify it.
So you already put your information 200 times? 

When you ask a question: most of the time you have to provide a little detail information. Is this your first time filing?
Is this your first time e-filing? If so, you have to call and get pin number. 
Did you file e-file? Did you get a rejected notice? 
Just to conform: the letter was legit, call IRS, find IRS number see if matches (you can check if the number is fraud). Have peace of mind about the legitimacy of the letter and your information were secured.

Call IRS : then do it as the agent says. If you have done your taxes online, you have to submit all the prints ( Federal and State ), attach your W-2 Forms, signed as a self-prepared.