I have the same problem. I contacted eBay customer service and they were so unhelpful.
They didn’t understand when I told them Royal Mail don’t always scan an item when they put it through a letterbox.
They just said it has a tracking code so I have to wait.
I put a similar message on here and people have told me the funds will automatically be credited after 14 days of me sending it if the status doesn’t change to delivered by the courier.
so it’s a waiting game for me at the moment.
EBay hasn’t really thought this one through when it comes to Royal Mail and I think lots of people will have the same problem. 14 days is a long time to wait for funds.