Between 2005 and 2010, Williams purchased a number of household items on credit from Walker-Thomas Furniture Co., a retail furniture store. Walker-Thomas retained the right in its contracts to repossess an item if Williams defaulted on an installment payment. Each contract also provided that each installment payment by Williams would be credited pro rata to all outstanding accounts or bills owed to Walker-Thomas. As a result of this provision, an unpaid balance would remain on every item purchased until the entire balance due on all items, whenever purchased, was paid in full. Williams defaulted on a monthly installment payment in 2010, and Walker-Thomas sought to repossess all the items that Williams had purchased since 2005. Discuss.