It won't do any good to talk to an agent. There is nothing Turbotax can do if you are correct that a return has been filed using your SSN. The IRS requires that once a return has been filed using your SSN any subsequent original return must be mail in. the IRS never sends Turbotax info that a return with your SSN has already been filed. It is the IRS that rejects your return not if you have state returns they must also be mailed in. read the filing instructions for what must be attached.
