a question about ebay!!?

[Girlie Electrics]

You can claim for each and every 'lost' package with the Royal Mail.
That will alert them to 'scam' addresses and any rogue posties.

You have to decide from a business point of view if RD is worthwhile.
You can Block every buyer who claims it hasn't arrived if you like.

Be sure to give a feedback along the lines of "Sorry to hear Royal Mail lost the parcel"
That will enable other sellers to see if it is a 'problem' buyer.
You can also contact ebay to ask them to look at (they won't tell you) if a buyer has a history of non-receipt.