Ya just link to wherever you have your artwork up for them to see it belongs to you 
After submitting two DMCAs to RageOn and never getting any reply, I found out their site was powered by Shopify, and that I could submit DMCAs directly to them, and THAT will get results, usually by the following day. So for anyone reading this, if your work has been stolen on RageOn, please submit your DMCA to Shopify, via this link: www.shopify.ca/legal/dmca