It is possible that you had an underpayment penalty on the tax return form 1040 line 23 but still had a refund on line 20a ... look at the return ... the amount on line 23 reduced the refund on line 19 thus the overall refund on line 20a. Usually the IRS processes refunds within 21 days however it can take longer especially at the end of the season when there is a last minute rush.
