As you are selling a scam-prone item (the iPhone), I suggest you go to My eBay > Account > Site Preferences > Buyer requirements and set up some blocks to help stop scammers from purchasing it.

Make sure you've selected to block buyers who have not been phone verified, and also block those with a primary postage address in a location you don't post to. While you're there, enabling the block on buyers with non-payment strikes is also a good idea. Also, don't believe anyone who wants to purchase it with unusual circumstances / conditions - they will often try to tempt you by offering more than the asking price.

Depending on what your current selling limit is, you may be able to get it raised by connecting a PayPal account or putting a valid credit (or Mastercard / Visa debit card) on file with eBay - that tends to get restrictions lifted from 10 items to 100 items per month.