Recover your account and change the details on a different computer, run a virus scan on your computer and be more secure in the future, simple steps, almost every RS Player gets hacked at some point, just gotta deal with it, only way to avoid it is to by literally MEGA Cautious, even the most experienced players can be hacked by clever scams/baits, i experienced being hacked of purple partyhat myself on a level 135 account which i have now lost both, just gotta deal with it :/