I have edited the first of your two latest posts to remove confidential serial numbers etc., which should never be posted to a public forum like this one. These are user to user forums, not a contact for any Magix staff, so no-one here can do anything at all about your request for a refund.
I have hidden the second of those posts, again because it contains confidential data but is also clearly merely a copy of the actual registration page. There is no point at all in posting such an item.
Where, exactly, did you actually purchase this specific version of Music Maker?