What to do if ebay awards item not received caseto the seller?

I bought a watch on ebay six weeks ago. The item was supposed to be delivered at 1pm (Royal mail special delivery) I waited until 1pm for it, but it came later in the day when I finally left the house to get lunch. I asked for it to be delivered on Friday when I'm working from home, but they automatically redeliver on the next working day (Thurs), when I was in the office and not able to redeliver the parcel. I asked for it to be delivered the next working day on Monday, but instead they attempted delivery on Saturday afternoon, when I was out. I tried to schedule a redelivery on the Royal mail app, but it shows an error. I went into the Royal mail sorting office twice over the space of the following month and they say they can't find it. However the tracking status on the royal mail app is still showing as "pending redelivery". I call up Royal mail and they said there's nothing they can do about it, I should contact the sender. I raise a case of item not received on Ebay, but they awarded the case in favour of the seller, because of the tracking status shows attempted delivery. They said that attempted delivery counts as delivery. I appeal the outcome of the case saying I don't have the item, but they said there's nothing they can do. What do I do now??