Builders Warehouse - no stock

I went to Builders Warehouse in Margate on the 11th of November 2024 which was Black Friday. I wanted to purchase the 5W Solar Stay On Floodlight which was advertised on the pamphlet and was told there was no stock. The staff member checked other stores on the South Coast and there was no stock in any of the other stores either. Why advertise an item for sale and you do not have stock.