Have you messaged the buyer? You could send them a polite message first apologising for the late delivery, but pleased to see that tracking has now shown delivery. Could they please repay you , and this to be done by cheque, bank transfer or a PayPal Friends and Family payment. Or, you can send them a PayPal invoice for the item.
Nothing though to enforce them to pay. If this was an expensive item, you may need to turn to legal advice to retrieve your money.
If you ever need to speak to a ' live agent' contact Customer Services at 8 a.m. when their lines first open, and at that time there's more chance of Dublin answering.
This is the easiest and quickest way to contact eBay Customer Services, for a Call Back option.
https://www.ebay.co.uk/help/eua?id=5275&mkevt=1&mkpid
Lines open 8 a.m. - 10 p.m. on weekdays
9 a.m. - 6 p.m. on weekends.
Automated agents will be available on chat outside of the above hours.
As said, I recommend contacting CS first thing in the morning as there's more chance of Dublin answering.
@edwar.varon