If the Click and Collect option is available, and you haven't had any luck with the postcode search for 'click and collect', then this item may no longer be available in the stores in your area for ‘click and collect’ and so cannot be purchased through the online store.
The item will be listed as available as it is able to be purchased from a nationwide location that may be outside your radius. This is when the message will pop up telling you to choose delivery if you then do not see the clickable option for delivery, then this is a clear indicator that the item is unfortunately sold out for delivery at this stage.
You are still welcome to visit your local store to purchase the stock there directly if it is available.