You need to contact Customer Services for advice here, and if there are steps for you to follow, to proceed here, aside from finding a 3 year old invoice !
I strongly recommend contacting CS at 8 a.m. on a weekday as there's more chance of Dublin answering, only speak to them, you'll know if it's Ireland calling, as it's a Call Back option.
Today and Bank Holiday Monday tomorrow, lines will open at 9 a.m. you can try then too, but as said, only speak to Ireland explain there's no possibility of finding a 3 year old invoice, so what do you need to do now.
CS can be contacted through this link....
https://www.ebay.co.uk/help/eua?id=5190
Good luck, please do come back and tell how you got on, hopefully with good news!
@srjgroundworks_3