Have you tried Help & contact?
https://www.ebay.com/help/home
Click through the options to get to the page where you can get a message like this (see attached). I have not tried, I don't know if you actually get a live person, but you should. If you don't get a satisfactory answer ask for the supervisor or call again. Some of these people have no idea about anything.
When you communicate with the seller, use ONLY ebay messages. For ebay, emails and phone calls are not considered proof. If you have not sent a message (only email) send one before you call, so when you call, the rep can look it up and see that you tried to communicate with the seller. IN the message indicate that USPS does not deliver packages heavier than XYZ (get the weight limit weight from the USPS site) but wait at least 24 hours with the call to ebay, after you sent the message. Also, take a photo of the oven and a
The seller is obviously dishonest. What you can consider doing if things do not work. Send the seller a letter asking him to arrange the transport of the oven back to them and use the label they sent you. It will show up as delivered. Now, if the seller and ebay are really uncooperative, ask for the refund, ebay will see that the return package was delivered and you get the refund ...obviously, in regard to the refund I am semi-serious, but if everything else fail, desperate times call for desperate measures, then it will be the seller who will be calling you and sending messages.
