I received a 4310c letter does that mean some definitely used my info

[AmyT · Accepted solution]

If you received IRS letter 4310C, it means that the IRS has identified a suspicious return that was filed using your social security number.

If you have not yet filed a return, it does mean that someone has used your information to file a fraudulant return.  

If you have filed your return (and it was not rejected), the IRS may just need additional informaiton to confirm your identity.

In either case, you should respond to the notice immediately with the information that the IRS has requested.