I am actually shocked that it worked in the first place. When I pressed the link, for some reason took an extremely long time to load up the page and when it did it looked like one of those generic survey websites. Like as in the rewards sections. But when I pressed the Steam for Slingshot people tab it redirected me and I put in the code which reduced the price to $0. It said an email has been sent but I am still waiting for it. Will update this comment when, and if, I get it.
Edit - I am not sure what is wrong but the email I have received just has a the Rocketr image and nothing else. Can I get some help OP?