Welcome to the Magix user to user forums. As such, no-one here can help you with any problem related to your account or registration, sorry!
It is the user's responsibility to save all the information pertaining to one's Magix account details. Do you have no knowledge at all of what email address you had and used at the time of initial purchase and registration? Have you tried to access your Magix account using any of the ones you can remember?
You could try emailing infoservice@magix.net and explaining the problem but whether they will be able to help you I have no idea.