You really ought to read the topic before answering; the OP already got their refund.
It should not be necessary to request tracking number; most sellers use eBay label printing and the tracking number is automatically shown in your purchase history next to that item.
If you get not paying buyers, you have to open NPB case, and close it as soon as possible. If you read the instructions, and followed them, you would have got your money back. Here is what the instructions say: “It’s important to close out any unpaid item cases. If you don’t close an unpaid item case within 36 days, we’ll close it for you, but you won’t be eligible for a final value fee credit.”
If you opened cases against the non payers they would have got a strike against them, and as most experienced sellers block people with strikes, these buyers would have found soon that they are unable to buy lots of stuff they would like.
it may be a good idea to read up on the way to use eBay if you want to sell there.