If someone else used your deductions or a false filing status of married when your filing status was SINGLE, you should file the IRS fraud form -Form 3949-A Information Referral.
You can file 1040 (or 1040-X) for tax year 2020 to get the stimulus payments EIP1 and EIP2, given that you did not already get them.
It could take a long time (years) for the IRS to resolve this.
