It usually takes up to 24hrs before Royal Mail updates the system, but unfortunately there's always the odd one where they don't ever update.
The only things you can really do is first contact Royal Mail's Customer Support and ask if they can get it to be updated, now if you have a Twitter account (I'm never calling it 'X'), it would be better to contact them there, as contacting by phone hardly ever goes anywhere, but I always get assistance by the Twitter team. Second is to use the confirmation by the buyer and ask eBay to make a decision and hope that they choose in your favour, but again on Twitter, contact @askebay, let them know what's going on and they will help... I'd actually recommend you go the Twitter route, I've always had a positive outcome that way!
