Click forgot account and reset your password. if banned it will say your acc has been locked and need to login on runescape(think it says you can use rs3) but basically go to runescapes site, login, if login invalid you need to recover your password cus someone changed it, if you can login go to account status and bang you can see if banned or not.
If you were handtraining but botting other accounts on ip then could get chainbanned and they'll give you a ban for "macroing(major)"