There really is no point all in SHOUTING as this is a user to user forum and there are no Magix staff here.
The registration code/serial key should have been in the email you received confirming the purchase of your Magix product. Have you checked it thoroughly?#
If it is not there, please email infoservice@magix.net and request their help.
Jeff, forum moderator, I can relate to Ady's frustration. I just bought what was touted as a suite of plug-ins and instruments etc. on sale until the 13th. Upon download, it was just Acid PRo Suite. No additional software. I already have Acid 365 so it was a complete waste of money. And I didn't receive ANY (oops, did I shout) additional registration keys for the promised software. The most frustrating aspect of all of this is exactly what you said in your response: "there is no Magix staff here". Is there even a staff? I've been trying to days to get help. There isn't even a support portal. @Ady, you're not alone. If I make any progress dealing with this I'll let you know.
Emails from Magix are occasionally deposited in one's spam or junk mail folders by the email host, so check those folders. Otherwise, as Jeff stated, email Magix and rationally explain your dilemma and include your purchase info. Maagix will certainly get the serial code to you.
btw, welcome to the Magix Sound Forge users forum @Ady.