Deleting the item doesn't open up any cases, it just deletes it from your sold page. On your selling page, on the left towards the top, there are menus and links. Click on deleted items. Find the listing you deleted and to the right of it, it should say undelete.
Go back to your selling page and refresh the page so the listing is back under your sold items list. On the right of the actual listing, click more actions, then resolve a problem. Select the option that you sold an item and the buyer hasn't paid. The next page will want you to confirm it. When the popup appears asking if you want to turn on the unpaid assistant, select no.
Go back to your selling page and refresh and you will notice under the listing that there is a case open. The buyer then has exactly 4 days to pay. If they haven't paid after 4 days, go back into the resolve a problem, scroll down to the open case, click the link at the very right. I can't remember what it says there, but you should be able to work it out. If you get to the next screen asking if the buyer has paid and the no option isn't highlighted, it means the 4 days isn't up. Up the top of that page it will tell you the exact time you can close the case, so go back in there then.
Whatever you do, don't leave the buyer any feedback if they don't pay. If they leave you negative while the case is open and you close the case without payment, eBay should remove it. If it doesn't remove automatically, contact eBay and they should remove it.
