Lopez Company sold merchandise on account to Atlantic Company for $4,000 on June 3, 2003, with terms 2/10, n/30. On June 7, 2003, Lopez Company received $200 of returned merchandise from Atlantic Company and issued a credit memorandum for the appropriate amount. Lopez Company received payment for the balance of the bill on June 21, 2003. Record the necessary journal entries on June 3, June 7, and June 21.