I would hold on to the check for now. If you are certain this is for your tax refund from 2016 you can contact the IRS to inquire about the recent check if this was a federal refund check. Please contact the IRS at 1-800-829-1040 for assistance.
Note: Since this is the busy season, there may be longer than normal hold times.
If the check is for a state tax refund, please see the instructions in the FAQ below to contact your state agency.
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