Once you buy accounts, first of all, what you need to do is change the password, and then set new recovery question answers, be sure you set each question and answer by yourself, and keep them in memory, three, set new registered email, and active the email by copy and paste the verifying code from your email.
after all that, you need to check the friend list, be sure friend list is empty, if you see lots of names there, just delete them. One of them could be Jagex Mod.
When you play Runescape, turn private chat off, in case of being bothered.
Now your account will be more safer.