What sort of information do you have from when you played? If you changed address, you can specify that and your location before. Old passwords are important. If you were previously a RuneScape member, providing payment details can help authenticate that it is you. You could also try tweeting @JagexSupport to see if they can advise you on anything else you may need to provide to ensure the account is yours. One more tip - from someone that successfully recovered an account a while back - if you are at all unsure about what the login name was at the time you made the account, giving the name of a couple friends on your friends list can help. If you are not using your original name for the character for account recovery, it will of course be rejected all the time.