Sellers are not allowed to demand more money after the purchase has been made.
On the last day for delivery, open a Not Received claim with eBay.
You have already contacted the seller so skip that suggested step.
If he cannot prove delivery (not shipping, Delivery) you will be refunded.
If he does not refund voluntarily, eBay will pay you and go after him for their money. And he gets a Defect on his selling account which can lead to higher fees, restrictions on the number and value of his listings, or even a closed selling account.
You can also leave feedback. The most effective feedback is calm and factual . Do NOT mention the dispute.
If the last date for delivery +30 days have passed, you are still covered by your Paypal account.
Go to Activities and again file a Not Received claim.
Again, if e cannot prove delivery (not shipping, Delivery) you will be refunded.
You can also if neither of those work, go to your credit card about a chargeback. Card policies differ but once again unless he can prove Delivery you will be refunded.
