I agree with Jelly that your post is not really clear. I thought exactly the same while reading it.

If you opened a real request, there should have been a link to ask eBay to step in  after 3-4 business days if the seller didn't respond to the request (not immediately though). The 21 days of inactivity is actually the correct time after which a request is closed though.

I would look into what Padi suggested at this stage.