Systems and methods are disclosed herein for processing transactions at an in-store POS where some of the items of the transaction have not been retrieved, i.e. the customer neglected to add a needed item to a shopping cart. A customer selects a product on a user computing device and invokes display of an optical code corresponding to an unretrieved product. A point of sale (POS) device then scans the optical code to add the product to the transaction. The POS device or user computing device may transmit an alert to a representative computing device instructing a store representative to retrieve the product and deliver it to the POS or some other location.