Just go to runescape.com login to you're old account then click this link, type Username a few old details and you're done wait for the email like I received
Support
direct link given from member below. no need to even log in
After a comprehensive review of this account, there is no evidence to suggest the ban was applied in error and normally would not return this account to play.
However we recognise that people change and as significant time has passed, in this
extremely rare case we believe you may have learned from your previous mistakes so would like to offer you one, final opportunity to continue playing this account, on the understanding that
you read, understand, and follow the RuneScape rules.
As described in
our terms and conditions the account creator is responsible for the account's behaviour, and we will apply any future penalties no matter who is playing at that time. Extenuating circumstances will not lead to the removal of a penalty, so to avoid any doubt we strongly advise you follow our guides on account security to prevent this from happening.
If you already have access to the account you can continue playing as normal.