If it's not showing in your email ( looked in Spam? ) , eBay messages or order details, then contact eBay Customer Services. It's essential you have this code or the store will not release the item, and to collect within 7 days.
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 for ' live agents' 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 recommend contacting CS first thing in the morning as there's more chance of Dublin answering.
@teambudgies