on 13-01-2018 6:35 PM
What do you mean by "PayPal details"?
If the seller is sending you a payment all they need is your PayPal email address, which they should have already if you bought somethng from them.
If the seller is giving you a refund they shouldn't do this direct anyway, but through eBay's resolution centre. If they simply refund you they won't be able to claim any refund of their fees, and may receive a defect from eBay for making a seller-initiated cancelaltion.
Without more information it's hard to advise. If the selelr doesn't needs advice on how to refund a buyer they can read eBay's guidance or ask here for advice.
on 13-01-2018 6:31 PM
The seller do not need your paypal details as he has already got this when you first made your purchase,,,,
Why are you retuning the item?
If you have opened a case, then the seller refunds through the case..
If it is change of mind, I hope you sent it back by a tracked method...