You have rightfully placed the ball into the buyer's court by asking them questions about which they have not responded.

If the case remains in this status, then after 30-days it should just time out and close in your favour.

However, they have been known not to time out, and in my case after the 30-days I called ebay and they did indeed close it in my favour when this had happened. It took a couple of days after the phone call to actually close tho.

It is risky for the seller to wait the 30-days... this is becasue at any time during this 30-days the buyer can simply come back to the case and escalate it without any further response to you. If they do this then ebay will instantly find in their favour and you will be awarded a defect of the worst kind for a case unresolved by the seller.

*** edited to correct a typo ***