Does the tracking actually show delivery?
You have also returned to selling after a little break, and sudden selling activity on a dormant account could be a sign of a hijacked account, so eBay wish to see tracking showing delivery, proving the genuine owner has returned to sell on the account.
Also, have you fully and correctly registered for eBay's Managed Payments? If not, this too could hold up your payouts.
See here:
https://www.ebay.co.uk/help/help/selling/getting-paid/introducing-managed-payments-ebay?id=4795
@boomoyse
