On December 31, 2019, Skysong, Inc. estimated that 2% of its net accounts receivable of $431,400 will become uncollectible. The company recorded this amount as an addition to Allowance for Doubtful Accounts. The allowance account had a zero balance before adjustment on December 31, 2019. On May 11, 2020, Skysong, Inc. determined that the Jeff Shoemaker account was uncollectible and wrote off $2,157. On June 12, 2020, Shoemaker paid the amount previously written off. Prepare the journal entries on December 31, 2019, May 11, 2020, and June 12, 2020.