Your location is set as Greece (didn't know anyone there could afford anything right now
) but you talk in UKP. Your real location (as in delivery address) could be a big factor in this so maybe you could clear that up.
You are doing the right thing so far in contacting the seller, sending him photos and suggesting suitable courses for resolution. The sticky point is what to do with the old item - you will need to send that back regardless of whether the seller refunds or sends you a new one, and the issue is shipping cost.
If you were UK based then that's a non-issue since the seller would have to carry the can. The seller is also no doubt a business (I think you need to be one to become top-rated) so distance selling regulations come into play. However, if you are in Greece then I don't know the local regulations or how Ebay.gr look at it.
Now you wait for the seller, but not for too long. There is a timeout for escalating things which is around 30 days in the UK, maybe different for you. Ebay help pages will tell you what it is, though. Either the seller will resolve things to your satisfaction or you will approach this deadline without getting anywhere. In the latter case, which includes everything from the seller ignoring you to negotiations not producing fruit, you must escalate to Ebay before the deadline. Go to the resolution centre on Ebay and start a dispute.
Suppose you have to carry the cost of shipping this item back... that's one of the problems of international commerce, I'm afraid. But also one of the benefits of using Ebay (for the buyer). I believe that the default stance for many areas is, or will be changing to, the seller having to cover the cost of returns where it is his fault (and bad shipping is his fault). But that may not have rolled out for you yet, or may never (particularly if you get booted out of the EU!).