You do not send the revision to eBay you send the revision to your buyer.
Is the feedback more than 30 days old ?
Try sending a feedback revision direct to the buyer otherwise contact eBay Customer Services but do so tomorrow morning when the lines first open at 8 a.m. as 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.
@laramol