Buyer hasn't paid, 4 days now, what do i do?

[ftlosm]

I listed something that ended Sunday, figured ok give them a few days it is the weekend, it's now Wednesday still no reply to the invoice or message sent via email to the buyer, I went to open an unpaid case for it so maybe ebay could reach them and get it resolved, yet when I enter the item number during that process it says

Open an unpaid item case

Enter Item number,

at this point I enter the number and it just takes me back to where to enter the number again, doesn't seem to "do" anything except says

Unpaid Item Assistant will open a case for this item on Jun 18, 2015 if payment hasn't been recorded.

So now I wait till June 18th to see if they pay?  I can get a few days maybe even a week but basically a month and then they will open a case June 18th?

I have never had that happen before where a buyer didn't pay, so this is all new to me, am I missing something, I did write to the buyer to their direct email and hit send invoice as well with no replies so far, so I guess I don't know what I am doing wrong on trying to get ebay resolutions involved.

Thanks