I need help understanding.

BEA4. LO 9.2 Window World extended credit to customer Nile Jenkins in the amount of $130,900 for his purchase of window treatments on April 2. Terms of the sale are n/150. The cost of the purchase to Window World is $56,200. On September 4, Window World determined that Nile Jenkins's account was uncollectible and wrote off the debt. On December 3, Mr. Jenkins unexpectedly paid in full on his account. Record each Window World transaction with Nile Jenkins. In order to demonstrate the write- off and then subsequent collection of an account receivable, assume in this example that Window World rarely extends credit directly, so this transaction is permitted to use the direct write-off method. Remember, however, that in most cases the direct write-off method is not allowed