False advertising

I recently decided to order a pair of shoes from the online store. I placed my order and paid for it and received the email confirmation that it is confirmed. 4 days later they say my order is cancelled due to the fact that they no longer have the shoe in stock. This is bitterly disappointing as this is false advertising and the refund will take 10 days to reflect - meaning I will not be able to give this gift to the intended person, nor do I have the money to buy the person a replacement gift. I will not be shopping here again.