Simply go to your Magix account, log in using the "wrong" email address and go to User Data and change your registered email address to the correct one.
If you have previously registered products to the wrong address, making this change should also change your product registration details. If it does not, you will need to email firstname.lastname@example.org, giving full details of the problem, i.e., both email addresses and the products registered to you and ask that they correct your user account details to include your correct email address and all your registered products.
These are user to userforums so no-one who posts here can help you, sorry.
Have you checked your account details as I suggested in my previous reply? If you have but can’t resolve the problem you must email email@example.com and explain what you need to be changed in your account.
Why should this website .. really check for emails? It is always the user’s responsibility to ensure he gives his email address correctly!