Mikah buys a new DVD player. After 9 days, he sees the same player on sale at another store for considerably less than what he paid for his. Since he still has the receipt, he decides to return the DVD player, get his money back, and buy it at the cheaper price. When he tries to make the return, he is disappointed to find out that returns on electronics must be made within three days of purchase.Which of the following responsibilities did Mikah most likely not meet?