With Paypal you have 90 days in which to file a complaint. If you used a credit card with paypal then you also have the ability to challenge the charge with the credit card company.
Now....speaking as a seller who uses Paypal as my credit card processor for daily business....
Once you open up a dispute with Paypal/ebay they instantly take the money that is being disputed and hold it in their own account. You don't have the money and the seller no longer has the money. Paypal is holding it in "escrow" because it's "disputed". This is true even if the transaction was 100% legit and the buyer didn't recognise the charge on the card so challenged it, etc.
Most buyers don't take that into account. As a seller - once the money is taken from me then I have little to no real drive to get to a swift resolution on anything. 1. It's already gone. 2. Even if you provide tracking numbers, pictures, emails, etc....paypal will almost always side on the side of the buyer - even when the buyer has failed to even return the merchandise. 3. If Paypal does come out of it on the seller's side - the credit card company can still reverse the charge to Paypal whenever they want. Paypal has no recourse with them - or at least says they don't - and will therefore instantly settle it in favor of the buyer.
I have had a situation where there was an item or accessory on the invoice that was not going to be in stock so I offered a refund to the customer on that part - they say cool but then file a dispute thinking that is how they start the refund....then they write the story to paypal, I write the story to paypal....the stories are the same, we agree. should just be a quick partial refund but Paypal will sit on it in arbitration for the entire time limit they give themselves. The entire time all of the money is in their possession. Honestly it's a huge racket.
So...as a seller....before EVER involving Paypal/e-bay with resolving anything please take the time to communicate directly with the seller. If you can't get a response then involve the other guys. Also FWIW - not hearing a response you like doesn't mean the seller isn't working with you.
It's a statement about the state of who we are when the first reaction is to assume a rip off and to go to the middle man first instead of the actual seller.