If you are a cash basis tax payer you report it when you receive it. I would include the overpayment in your 2022 tax return. Then next year you report any paybacks as an expense. But you are not paying it back to them. You are crediting the invoices. You don't report anything for it on 2023. So you will just have less income in 2023 to be taxed on. You only report your actual income when you actually get it. Hope that isn't too confusing.
