Any buyer on eBay can file a claim with eBay and their payment processor, bank or credit card.
If the buyer uses a credit card issued by a bank through PayPal then they can file four separate claims. The last time I checked PayPal allowed a time frame of 180 days.
These third parties will decide the fate of the claim and not eBay.
The buyer’s claim can be based upon anything the buyer wants to make up. There is no actual investigation in 99% of the cases, which are simply rubber stamped by these third parties and then rubber stamped by eBay.
Once a package reaches the freight forwarder this does not any way provide you with protection. The buyer can claim the package has something else in it. They can substitute a broken copy of what you sold them and claim that is what you sent them.
A tracking number does not prove the buyer got the item or that the item was as described. It only proves they got a package.
On the other hand when a buyer runs a return scam by only mailing back a empty envelope with their return label that does prove the buyer returned the item in eBay’s eyes as the tracking number says so. eBay will claim that its your word against the buyer. eBay will claim you could have removed the return label from the package the buyer sent back and put it on a envelope yourself to make it appear the buyer is thief.