Go to help & contact at the top of the ebay's page and type in click and collect.  There is a lot of info there which will answer your questions.

If you phoned a Woolies that doesn't do c&c they may not know what you are referring to.

Basically instead of sending the item to an address, it's sent to a Woolies or bigW that the buyer can select from a drop-down box.  It can be useful if you can't get to the PO during office hours.  But some buyers have experienced that it can take a day or two longer.