You have three basic ways to get a refund when you do not receive your item.
If you have not received your item after 20 days (from North America, from Asia allow 30 days) :
Go to the Resolution Centre at the bottom of this page and open an Item Not Received Dispute.
If the seller cannot prove delivery, he is required to refund you in full.
If the seller does not refund you voluntarily, eBay/Paypal will refund you and go after him for their money.
There is a deadline on this and you have probably passed it.
So.
Go to your Paypal Account.
The Resolution Centre is on the left side of the page.
Open an Item Not Received Dispute.
If the seller cannot prove delivery, he is required to refund you in full.
If the seller does not refund you voluntarily, Paypal will refund you and go after him for their money.
There is a deadline on this, but it is about 180 days (six months) from payment.
Do this today.
If that doesn't work out, and there is no reason to think it won't , go to the credit card you back your Paypal account with, phone the 1-800 number on the back and ask the customer service clerk about a chargeback.
Cards vary in their standards for chargebacks.
There are strong protections available, but you have to start the process. No one can help if you don't ask.