I filed taxes for 2014 months back, got the return, and all was well. Then I got a series of tax return emails over the course of two days (in June 2015) from a different seemingly legit site (1040.com), indicating that someone has filed a return with my name and email address. The return was apparently declined by the IRS, then resubmitted and subsequently accepted by the IRS.
I do not know anything else yet about the event (such as if my SSN was used). I'm baffled why someone would use my email address unless it's a phishing attempt, yet there is no indication of phishing. Nor is there any evidence of email tampering.
If I've already filed, do I have nothing to worry about? Should I report this to the IRS even if there's no evidence of actual fraud (so far)?