Q: An invoice for $36 was not entered in the debtors journal. Please advise whether to credit or debit on reconciliation...
A: Well, an invoice here indicates that a sale was made. And a sale means debit the debtor (and credit the income). If this transaction was not recorded, it means the debit to debtors was not recorded. So now you need to record it. So you enter a debit now on reconciliation. Make sense?