IRS billed us an additional $392.92 for Recovery Rebate Credit after using TurboTax. Why?

sylvianigliazzo,

The Recovery Rebate Credit was a 2021 tax form credit.  If, as I suspect, you recently filed your 2022 taxes, then the IRS letter just coincidentally happened to arrive shortly afterwards.  Look at the letter and see what tax year it refers to, most likely the tax year ending 12/31/2021.

On the other hand, if you recently filed your 2021 return, albeit long after the regular filing date, then the IRS had determined that either (a) you had already received that credit via check, direct deposit, or debit card or (b) you had miscalculated the amount claimed on your 2021 return.  First check your bank statements and any notices that you had received regarding the 2021 stimulus to see if you had indeed already received it.  If, though, you can find no evidence of receipt go to IRS Get Tax Transcript to see if one was issued.  If so, you will want to call the IRS at 800-919-9835 and have them trace the payment.