CP268 tells you we made changes to your return because we believe there is a miscalculation on your return. To avoid additional penalties, pay the tax bill you received.If this results in a net over payment, a refund will be sent to you. You get an overpayment credit when your tax payments exceed what you owe. You'll automatically receive a refund of the credit. In addition to filing a completed, verified Claim Form, the claimant must also fill out and file applicable documentation described in. 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. Dropping classes or failing to attend can result in a financial aid overpayment.