PNC gave a link to the actual page where you can add buyers to block them. If you go here https://www.ebay.com.au/bmgt/buyerrequirements you can also set buyer requirements to block serial non paying pests. Tick to block buyers who have 2 or more unpaid cancellations in the last 12 months. Also helps to tick to block buyers in a location you don't post to (e.g if you don't post overseas). Select to not allow blocked buyers to contact you (although they can if they have been in a transaction with you in the last 6 months). Then select to apply to current and future listings.
