The way I learned it is: Any statement of intent, no matter in which form, is creating a contract that you are bound to abide.

You sound like you would argue that it obviously was not a contract but a joke because 'why would a company pay something without getting anything in return'. But that would not hold. Companies spend a lot on customer relationship management. So the customer here could safely assume that the companies 'return' was a happier - in this case: less angry - customer.

http://theexaminer.com/features/commentary/promise-make-gift...

https://dolanlawfirm.com/2017/01/oral-promise/

A happier customer is not valid consideration for a contract. That would turn every pending gift into a contract and that's not how the law works.