Before we can determine how to treat the repayment, we'd need to know if any of the Social Security benefits were included in your taxable in 2022 and 2023. Can you check your 2022 and 2023 tax returns to verify if any portion of these benefits were taxed? The taxable portion of benefits would be reported on line 6b.
If none of your benefits were taxable for 2022 and 2023, there'd be nothing to do since you haven't paid tax on it.
If you did include some of the benefits in your taxable income, you would only be making an adjustment for the amount that was included. Depending on how much the taxable benefits were, you'd either 1) take an itemized deduction on Schedule A for the amount that was repaid or 2) calculate the difference you paid in tax in those years and the tax that you would have paid if you hadn't included those benefits in income - the difference would be a credit on your 2024 tax return (available if the benefits were at least $3,000).
