If you received the 3rd EIP payment you should have received letter 6475 from the IRS. You can also check your own banking records for deposits of $1400 per person in 2021, or you can check your online IRS account to see if you received the 3rd payment.
https://www.irs.gov/payments/your-online-account
If you did in fact receive that payment, and you said on your return that you did NOT receive it, then there will be an amount on line 30 of your Form 1040. If you received the payment already---then you should not have an amount on line 30. The IRS is going to cross check returns---they know if you received the payment. If you put it there by mistake they will take it away----and that will delay your refund. You do not need to amend or do anything about this---the IRS will take care of it if necessary.
PREVIEW 1040
https://ttlc.intuit.com/questions/1901539-how-do-i-preview-my-turbotax-online-return-before-filing
Click on Tax Tools on the left side of the screen. Click on Tools. Click on View Tax Summary. Click on Preview my 1040 on the left side of the screen.
As for not receiving the 1st or 2nd stimulus checks---if no one could claim you as a dependent for tax year 2020, then you can file a 2020 tax return in order to get those payments----IF you really did not receive them. Again---look at your online IRS account to see if the IRS says you got the payments.
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**
