I would message them via ebay so there is a record.

I would not ask if there was a problem, not if your listing was clear and it seems it was.

Just ask what day they would like to pick up the item & give them a list of some times you are available. Don't give your address, just the times eg Wed-Fri between 6-8pm or whatever.

The ball is then in their court and if you hear nothing, send another message after 4 or 5 days with another question as to what day suits them to pick up.

At least if you message them, and they complain, you can direct ebay to view your ad, view your efforts.

Now, it may be that they will realise eventually that the item is pick up.

They may contact you & say they can't do it.

You may have to then organise a refund.

But until they ask about it, I wouldn't, as you don't know for sure they are not planning on having it picked up by a friend or relative.