Did you file a joint return in 2020 or 2019? If you did then both you and your spouse would have gotten a letter 6475 showing you each got the $1400 stimulus payment ... even if you did not get the letter you had to enter the amount you & the spouse did get from your records. So if you got the 2800 and said you only got 1400 then you did not complete that section correctly and the IRS caught the mistake and adjusted the return automatically.
Now if you did not receive $1,400 for the third stimulus payment, the IRS may think that you were already issued the third stimulus payment.
At your IRS online account, you can find whether a payment was issued to you that you did not receive. You can also find this information on your tax transcript.
If you need to trace a payment that the IRS says has been issued to you, mail or fax a completed IRS Form 3911, Taxpayer Statement Regarding Refund.
Once you resolve this issue you can amend for the missing credit (if it was truly missed).
As of April 7, the IRS had issued 9.4 million math error notices — and 8.3 million of these notices were related to the recovery rebate and the child tax credit. These cannot all be software errors.
Where's My Refund? IRS has some answers but others left clueless (freep.com)
