i haven't played in a few months somehow i can login to the website but not to the client. My password is case sensitive and ive tried every possible way but it still won't let me login. For some reason it lets me login to website just fine. plz halp
In order for us to better assist you, we would need more information as to what exactly is going on when you try to log into the game. From the looks of it, it seems like you have the Authenticator enabled on your account and you need to provide the code in order to be given access to the game. If you don't have access to the phone or computer you used to enable the Authenticator, then you must disable it and enable it again.
Then, head to this other Support article: Disabling the Authenticator (Click ME!). It will allow you to disable the Authenticator if you have access to your current registered email address. If you don't have access to the current registered email address, then you need to recover the account first so that you can add a new email address. You can only disable the Authenticator by doing it yourself through email.
All the steps required are included above on the article I have quoted.
I recommend you check the time synchronisation of your devices. Read the 'Authenticator code not working' support article linked above by Wynd.
It sounds like an Authenticator problem even though the error message you are getting does not indicate that.
You could even disable your Authenticator and set it back up again and that should fix the problem. Note also that Runescape passwords are not 'case sensitive'. There is no upper case/lower case in an RS password.