Don't deliver at given date and no communication on way or when

So they advertise items in Stock and available, on the date of delivery they have not processed the order yet, had to phone them because they don't respond to their helpdesk request. Now the item is not available at their stores, and they cant change the delivery address, even if it is their fault that i wont be able to collect the order at the address i supp**** with the delivery dates they gave. And they don't communicate that the item is not in stock anymore but check the website it says available for same day collections how is this possible.