I cannot say for certain why that happened but please click here for some possible reasons.
To verify your refund amount:
If you filed a Form 1040, the Refund Amount is shown on Line 20a.
If you filed a Form 1040NR, the Refund Amount is shown on Line 73a.
If you filed a Form 1040NR-EZ, the Refund Amount is shown on Line 23a.
If you filed a Form 1040PR, the Refund Amount is shown on Line 13a.
If you filed a Form 1040SS, the Refund Amount is shown on Line 13a.
Please wait at least 24-48 hours after your return has been accepted by the IRS to check your status on www.irs.gov/refunds.
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