When the automated systems at the IRS detect a problem with your tax payment you will receive a form 5564. This form might arrive because the income you provided on your tax return did not match your employer’s records. You could have also simply miscalculated the total deductibles and tax credits, causing the discrepancy. If you agree with the deficiency and are ready to fix it, sign the form 5564 and return it to the IRS. In order to dispute the deficiency, you will gather information and statements to support your claim and send them to the IRS with form 5564.