Buyer has not paid for item I posted, despite promises they would pay

barbiedoll

You have proof of posting, proof of delivery and emails from buyer stating that he has goods. You also have his name and address.

Send a "letter before action", giving him (for instance) 14 days to pay or else you'll start legal action to claim the payment. State that you have proof of delivery.

You can file a small claims court action for a few quid, and if he realises that you're going to take it all the way, he may just pay up for a quiet life.

Obviously, if this is for an item that you sold for a fiver, you should probably just let it go and treat it as a learning experience!