CP268 tells you we made changes to your return because we believe there is a miscalculation on your return. You get an overpayment credit when your tax payments exceed what you owe.You'll automatically receive a refund of the credit. You received this notice because the deposits or payments applied to your account didn't agree with what you claimed on your federal tax return. The Department will send a garnishment release letter to the taxpayer's employer once the tax liability is paid in full. You can find the CP or LTR number on the right corner of the letter. How do I apply for Child Support Services? You can complete the application at your local CSS office or apply online. For tax forms, call 1-800-TAX-FORM (1-800-829-3676). You do not need to respond to this letter.