Did you buy from an authorised seller for said battery?

Don't risk buying such things from some random

You don't need to ask the seller, you open a dispute within the time limit

Did you use it for longer than the 30 days eBay provides?

If you did not buy from an authorised seller, there is no warranty, so no, they won't do anything

How did you as a seller rectify the neg you received ?

OP, a moderator will be along to remove the seller username shortly.

No matter how annoyed or upset you are if a purchase did not go satisfactorily, it’s not permissible to post any eBay usernames of buyers or sellers in an attempt to out them or shame them for bad behaviour. These are public boards run under eBay’s auspices and there are community guidelines that specifically prohibit this; you would have seen a pop-up warning when posting, advising you about not entering personal or identifying information etc.

If your seller is not registered in Australia, then unfortunately you have no cover in terms of ACL. If you need a warranty for an item, it really is best to buy from a seller whose eBay account is registered in Australia (if you are buying on eBay), who is an Australian business with ABN, and who is authorised by the manufacturer (or authorised local distributor) of the item to sell that item in Australia.

While eBay offer a 30-day Money Back Guarantee, that’s not the same as a product warranty. It’s about whether an item is as described upon arrival.

It may be that the item is in fact not as described (the specs aren’t as in the listing, it’s not the brand stated, it’s a fake, etc), but you still need to open an INAD dispute no later than 30 days of the item’s arrival. The MBG doesn’t cover you for a millisecond longer than that timeframe.

It may be that you can have your bank do a chargeback if you funded your purchase with your card, within a longer timeframe, if it’s the case that what you received isn’t what you ordered… but (and this is important) if you bought a cheap unbranded item and received a cheap unbranded item, it may be that you haven’t any recourse.

What is the item number? (Not order number - just the item number of the listing from which you purchased…)