The stay campaign has known for three years that a referendum was coming, and they got a four month notice of the exact date, so they had plenty of time to make their case to the people. They tried. They lost. You don't get to keep asking for do-overs until you get the result you like. Suck it up and move on.
As our President once said: "Elections have consequences."
"If you like your geostrategic bloc, you get to keep your geostrategic bloc."
Aaaaand now I'm cleaning coffee off my monitor screen. lol.