It is sounding as if you did buy something from this seller.
It is also clear that they don't have the stock of whatever it is you bought.
Therefore, the sooner you get a refund, the better.
If I were you, I would probably message back that if they are out of stock, then you would expect an immediate refund.
Because they are offering to refund you, I don't believe it is a scam in the sense you mean.
If you were not to receive the refund quickly or if the item didn't arrive by the estimated arrival date (which the seller has admitted is the case) then you would need to open a claim directly with ebay, immediately, for a refund.
What is happening here is that the seller has sold something he doesn't have, something that is out of stock.
Cancellations aren't all that rare, they happen. Sometimes it is because of being out of stock, in which case I think the seller's account can be affected. But sometimes cancellations are because a buyer requested it, in which case the seller's account is not affected because it is not the seller's fault.
That is what I think the seller is angling for.
He wants you to reply that you want to cancel so he can mark it as a buyer request.
I do believe all the talk about the item being accidentally damaged is quite possibly rubbish and they are just out of stock at the moment. But regardless, you may as well accept the refund asap so you can look elsewhere for you item.
Just make sure you check your account and that the refund really is forthcoming quickly.
