If, despite precautions, a discount product is out of stock during the campaign period, the key to resolving the situation appropriately is good customer service.
In case of delays or mistakes:
For example in selling by post or online consumers may place an order for a product without actually communicating with the seller. As such, a contract is created between the parties when the consumer sends his response. In selling on the internet the requirement on the business to take due care is highlighted because of the ease of keeping web pages up-to-date.
The appropriate corrective action in cases of defects can include, amongst others: