a return is simply not an option at all.
Great, so that's the end of the story then. If you do not want to return the pony, then you do not get a refund for the pony. It's pretty straightforward. It would be the same at any store you'd visit in person, so why should it be different for ebay? You are
choosing to keep the pony. It is not an impposibility to return it, it is a choice that you are making that you want the item enough to keep it. So if you are keeping it, then you do not get a refund. I agree with Maniah that at this point you are just continuing on for no reason. You have made your decision to keep the item rather than return it for a refund, so there's nothing else to say on the matter.
Also re: communication time. Ebay just says
preferably within 24 hours, that's not a hard and fast rule. Buyers need to be aware that sellers have other responsibilities as well as their auctions.