Already rec'd refund. Just realized SSA-1099 was not included. Line 11b on 1040a is $23056. Box 5 on SSA1099 is $15,420. Now its showing I owe $$$. What to do????

[CherylW · Accepted solution]

Since you've already received your refund, enclose a check or money order with your amended return (follow Turbo Tax instructions) and mail it BEFORE April 18 to avoid penalty.