I feel for you Marius.
I have recently had an eBay transaction go bad. Its the sense of sweet victory turning sour.
Our cases are not so similar in cause but have had the same effect, returned funds.
In my case i instantly contacted eBay but there "investigation" as far as i could see was to send me a standard form answer stating how important i was to them as a customer and how they take complaints seriously. Then no contact or action for days on end. I wrote twice more asking for an explanation but did not even receive a reply.
A good friend that sells heavily on eBay told me that if funds are returned (for whatever reason) eBay have a way too relaxed approach to the issue - prefering to use any investigative powers for disagreements where there is outstanding funds.

My advice : act firm and friendly to the seller. Dont make him your enemy and then ask for his proof that there were technical faults with the auction.

BTW - nice quartz Heuer - good luck on this one.

- Darren