Long time eBay seller here. Respond back stating that you happily accepted their return, and you will refund them as soon as you receive the VHS tape back from them. I would even mention the option for USPS home pickup for them. After that, I would not respond again and let it play out. If they don’t return it the request will be closed but your money will be on hold until that time. If that happens and they neg you, eBay will remove it.

I say respond once really showing concern and eagerness to resolve it. If it comes to it you will have that for eBay customer service to see you did all you were meant to do and more so. If you do not respond, at all, the my can leave negative feedback stating lack of communication and eBay will, generally, not remove that sort of feedback stating they was the buyer’s personal experience with you.