An overpayment of tax happens when you have paid more tax than you were liable to pay. If you have overpaid tax you will get a tax refund. You must claim a tax refund within 4 years of the end of the year in which the overpayment arose or you will not get a refund. At Anytime Tax Refunds we can review your taxes for the previous 4 years, complete our quick and easy application form and let us do all the work.