I Paid My Taxes But The IRS Says I Didn't!

Sometimes people pay their taxes on time but the IRS says they didn’t. This is a result of the IRS not “posting” the payments correctly on their computer. You should always write on your checks your name(s) as they appear on your tax return, Social Security number(s), form you are paying for, i.e. “1040” if paying with your return or “1040ES” if making estimated tax payments, and the year you are paying for, i.e. “2009” if paying with your 2009 return or “2010” if making estimated tax payments with the 2010 voucher. That’s probably the biggest error in posting that occurs- the payment is applied to the wrong year.
So if you receive a notice from the IRS saying you owe taxes that you think you paid here’s what you do:

Call the IRS right away and tell them. Get the cancelled checks showing all of your payments. Make copies of the front and back of each check. Then send them to the IRS with a letter explaining what happened.