As soon as a Classified listing goes live even for a few seconds that non refundable listing fee of £19.99 is charged.
If it was cancelled within a few minutes it is worth contacting Customer Services explain the error that it was cancelled immediately, they are not obliged to, but may refund you that listing fee.
Lines are open now, but I recommend to wait till lines open tomorrow at 9 a.m. when there's more chance of Dublin answering, worth speaking only to them.
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, recommend contacting CS first thing in the morning as there's more chance of Dublin answering
@zombieslayercave .