Dora Alexander, owner of Passions Linen Shop, was preparing checks for payment of the current month's purchase invoices when she realized that there were two invoices from Sensuous Linen Company, each for the purchase of 100 red, heart-imprinted king size linen sets. Alexander thinks that Sensuous Linen Company must have billed Passions Linen Shop twice for the same shipment because she knows the shop would not have needed two orders for 100 red linen sets within a month.
1. How can Alexander determine whether Sensuous Linen Company billed Passions Linen Shop in error or whether Passions Linen Shop placed two identical orders for red, heart-imprinted linen sets?
2. If two orders were placed, how can Alexander prevent duplicate purchases from happening in the future?