How to delete SwiftKey data?

I would like to delete all my SwiftKey cloud data because I want to start from scratch. When I go to data.swiftkey.com and press on the big red button "delete backup", a small window with a turning circle appears, telling me "in progress", but it stays there forever, and when I go to the hamburger menu and open "view data", I can see that all my data is still there and absolutely nothing was deleted. Also, when I go to "Permanently delete my account" and delete my account, which is supposed to be permanent , I can just log back in at a later date and see that neither my account nor my data was deleted.