Neco 2020 Financial Accounting Question 21

During the month the cash book shows an opening balance of ₦12,000. Receipts recorded are cash sales of ₦45,000, a loan of ₦10,000 and a customer payment of ₦8,000. Payments recorded are rent of ₦15,000, salaries of ₦20,000, purchase of inventory of ₦12,000 and a bank service charge of ₦500 (which appears only on the bank statement). The cash‑book balance at month end is recorded as ₦27,500. The bank statement shows a balance of ₦30,200. Outstanding checks amount to ₦3,200 and deposits in transit amount to ₦2,500. A cheque received from a customer for ₦4,000 was later dishonoured and appears as a deduction on the bank statement but was recorded in the cash book as a receipt. Assuming all other entries are correct, what amount of cash receipt was omitted from the cash book?