Click on "support" at the top of the page and check if there's a support article relating to your query. The aim is that the articles will solve common issues without the need to submit a ticket, but if it doesn't there is a 'contact us' button located at the bottom of [most, but not all] articles.
e.g: at the bottom of this article about refunds there's an option to contact Jagex regarding payment support: https://support.runescape.com/hc/en-gb/articles/205981571-Refunds
07-Aug-2016 04:56:10