how to categorize a payment received in 2021 where taxes were paid on the income in 2020?

I paid a supplier in 2020 for an item and paid taxes on the income received in 2020. The item was returned to the supplier yet the supplier did not return the amount paid until 2021. How do I categorize a reimbursement received in 2021 where taxes for income were paid for that item in 2020?