eBay provides a very straightforward avenue for being refunded when an item is not as described. It hasn’t anything to do with eBay customer support, but rather with eBay’s MBG.

The Money Back Guarantee covers you for 30 days from delivery of the item, or from latest Estimated Delivery Date (EDD), whichever is sooner. If the item you received was delivered no more than 30 days ago, you should open a return/refund for INAD immediately. Once the timeframe has passed, it’s no longer possible to open a dispute. The timeframe is precise to the very nanosecond; the MBG process is automatic, bot-driven, and there is no leeway with time.

If the timeframe is longer than 30 days from delivery, you’re no longer covered by the MBG. You could try a chargeback with your bank if you funded the purchase with your credit or debit card.

If the item was received rather more than 180 days ago, and the problem is that an issue developed with the item over time of after several uses, then you wouldn’t be covered by the MBG anyway, as it is a guarantee (of item as received), not a warranty. The same is true for items funded by PayPal. 

For items covered under warranty, you will need to meet the ACL conditions (Australian Consumer Legislation), buying from Australian seller, where that seller is an Australian registered business with ABN/ACN, and that seller is authorised by the product manufacturer to sell that product.