Hi and welcome to Just Answer!There is no other way to clarify the issue - but to contact the IRS. The IRS general contact is 1-800-829-1040. Unfortunately a simple phone call may be very time consuming.You may also visit your local Taxpayer Assistance Center where you can talk with an IRS representative across the counter. No appointment is necessary - just walk in. Here are locations in your state. http://www.irs.gov/localcontacts/article/0,,id=98259,00.htmlPlease verify if the notice mentioned any missing documents.
I will try phoning again. Thanks