if they haven’t arranged to pick it up in a week then next step would be refund?
Whatever you do, don't refund without going through the correct process.
Basically (assuming they're not going to collect) you have two options to get things resolved properly.
Either file for non-collection; not sure how this is classified in ebay but if they don't respond, eventually ebay will cancel the transaction and refund your fees; OR the buyer has to request that you cancel the transaction. Once they've requested it you can cancel yourself and again, you'll get your fees refunded.
Unfortunately there's nothing to really force a buyer to complete a purchase if they don't want to. Even after the sale, ebay still gives buyers a lot of rights.
I've had items turn up and before I've even opened the package I've raised a return and sent an item back as I'd changed my mind over the couple of days it took to arrive.
Risks of being a seller unfortunately. Luckily very rarely has this happened to me the other way round!