I'm not completely positive what problem exactly you're having. Are you saying that you just didn't receive the e-mail with the activation code and download link after purchasing the Movie Edit Pro 15+ download version on the Magix website? In this case you might want to verify that your order actually went through and your e-mail address was correct. Check your spam filter whether the e-mail with the program details was possibly intercepted. If in doubt, get in touch with Magix sales/support and ask them to assist and resend the download version details.
If you did receive the e-mail and you're having problem with the download, make sure you get the complete URL. If it is displayed broken up over several lines in your e-mail client, just put it back to together via copy & paste in your browser address bar. I guess you could also download the MEP 15+ trial version from the website by just clicking on the download link: