Did you use a tracked service?
If you did, go to the Resolution Centre at the bottom of this page.
Open an Item Not As Described dispute and enter the tracking number, even if it does not show delivery. It will soon enough and there is a deadline on Disputes.
BTW, the first step is to Contact the seller, but you have already done that when he instructed you to return the item.
When the parcel shows as received by the seller, he is required by eBay to refund you. If he does not do this promptly, eBay/Paypal will refund you and then go after him for their money. They will not be happy with him and he won't be happy with how they show that.
If you did not use a tracked service.
Well. Sigh.
Okay, try this. Go to the credit card you really paid with (PP is just a useful mediator) and phone the 1-800 customer service number.Ask the clerk about a chargeback.
She will need information to refund you: dates, transaction numbers, payments, currency, tracking number on the parcel.
Cards have a longer deadline than PP, but they do have deadlines. So if PP can't help you, don't delay going for the chargeback.
Some cards will also want Confirmation of Delivery, so I do hope you tracked the return package. Some will accept proof of mailing which is cheaper.
