To see it on your orders you probably need to change the period showing. There's a link todo that at the middle of the top of list of sold items.
If you've bought your own label to add the new tracking number you still need to generate the original prepaid label. Then go to the More Actions dropdown menu or View Order Details > Postage > Track Package > dropdown arrow and change the tracking. That must be done on a desktop browser, not on your phone.
But even if you can't manage to do the above the payment will be released anyway in 14 days.
If you still have problems with it you can contact ebay by requesting a callback on here:
https://www.ebay.co.uk/help/eua?id=5275&mkevt=1&mkpid
@orangefizzy