Before you call CS, can we ascertain a few more details please.
Did you open a case for the return, were tracking numbers showing the item was returned?
Did you open the case in time, that is, within 30 days of the item's last estimated date for delivery? If opened later then the case was closed as you claimed too late with eBay, and now you'll need to turn to your payment provider for help with your refund.
If you still need to contact CS:
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.
I do though recommend contacting CS first thing in the morning as there's more chance of Dublin answering.
@webstbri_ykbuede