False advertising on out of stock product

False advertising of unavailable product,i spent 3weeks going to the store for one product as i was kept being told that they have placed an order it will be delivered all my time and petrol wasted ,up until the promotion ended from 7 till 20 September,just after it ended then they have it on stock when I enquired with store manager she advised that she can not do any rain check as the promotion is finished this is unacceptable why would you put a product which is out of stock on promotion then have it available after