When you connect to Internet and browse, every page address you visit is memorized by your browser which include cookies. Those files and cookies are not essential, many people consider those files and cookies as junk. If you keep getting the message "Account temporarily unavailable" it could very well be because of a cookie in your mobile phone.
Deleting temporary files and cookies will also increase your phone's memory and browser speed.
Temporarily unavailable means Temporarily! don't try again again open your account after then Facebook team will be deleted your account so please just leave that and try again login your account in a 3 days