Locked out of Cloud & App store

After loading ios12 in Dec, it wiped 55 files off my iPad notes & it ask me to sign in on my setting for iCloud,, iCloud takes my password but post this statement, “ your account has been locked because of security concerns”, then posts, “activate account?” I go thru the circle of retrieving my password inputting it & it leads me back to sign in post of “your account has been…. It’s a glitch caused by iOS 12 bug that wiped my accounts out because I’ve not logged out of ICloud in many years, I need to access my App Store acct to deny 3 unauthorized purchases 2 in Australia & 1 in Germany. What do I do?