Welcome to the Magix user to user forums, so not a contact for any Magix staff. Also, since this is a public forum, confidential data like order and serial numbers should never be posted here; hence, I have edited your post.
To resolve your issue you need to email infoservice@magix.net, giving full details of your original purchase and ask for a new activation code. My understanding is that such codes are for single, one-time use only, hence your problem.