Let's step back a little.
Has the item arrived? The delivery dates from postal systems tends to be ...optimistic. Personally I would allow 10-15 days from Europe, 20 days from North America and 30 days from Asia.
However, you have contacted the seller and the result is unsatisfactory.
Don't leave feedback yet. That's complaining to your friends
Complain to the 'police'. The eBay/Paypal police.
At the bottom of this page is the Resolution Centre. Click on it and open an Item Not Received Dispute.
The first suggestion is that you contact the seller. You've done that . On to Step Two, getting your money back.
If the seller cannot prove that you have received your purchase, he will be told to refund your payment.
If he doesn't do that promptly, Paypal will, and go after him for their money.
There will be other fallout for him , and it will not be pleasant.
Compared to that fallout, some grumpy feedback would be apple pie and kisses.
