In recent years, eBay have been known to protect buyers over sellers. It can be a tough world for sellers if a buyer claims that they didn't receive an item. If you have PayPal you get seller protection. If you don't have PayPal then you don't, which means that there is not much chance of you solving the case in your favour unfortunately.
PayPal is a quick payment system, whereas a Postal Order for example would take a long time to process and there is no proof for the buyer to say that they sent you it. Buyers don't want to chance it.
PayPal is the way forward, but if you decide not to use it, just be careful
