What is the double entry when the bad debt is not recovered?

How bad debt transactions are recorded depends on the whether the entity uses the allowance (GAAP) method or the direct write-off (non-GAAP) method.

Under the allowance method, the entity calculates, based on experience and other factors, an estimate of anticipated unrecovered debt for the year, and records that amount as the Allowance for Bad Debt (or Allowance for Doubtful Accounts, or Bad Debt Provision, etc.). The allowance is a contra account to Accounts Receivable, and permits receivables to be reported at their net realizable value.

dr Bad Debt Expense, cr Allowance for Bad Debt.

When the sale is first transacted, dr Accounts Receivable, cr Sales.

When an unrecoverable amount has been determined, cr Accounts Receivable, dr Allowance for Bad Debt.

Using the allowance method, the write-off of bad debt has no effect on the Profit & Loss. The entry simply removes the receivable and reduces the allowance account.

If debt is subsequently paid, reverse the write-off entry, then record the receipt as usual.

dr Accounts Receivable, cr Allowance for Bad Debt.

dr Cash, cr Accounts Receivable

If the entity uses the direct write-off method, any amount determined to be unrecoverable is posted directly to Bad Debt Expense.

dr Bad Debt Expense, cr Accounts Receivable.