How long do I have to file an appeal to an overpayment determination? July 21, 2021 20:45 Updated The appeal must be filed within thirty days from the date the overpayment determination was mailed. Related articles What can I expect after I file my appeal? What happens if I am overpaid? What if I disagree with the overpayment determination? What is an example of a situation that would cause a fraud overpayment? How do I get set up to pay state unemployment tax?