i just purchased Music Maker Plus edition from Best Buy today. Went home to install, input the voucher code and it was supposed to email the serial number... it didn't. So now my code is invalid and i dont have a serial number, now what?
The email is sent within minutes of entering the voucher code - did you check the spam folder of your email ?
Also check if the serial number has appeared in your Magix account - got My Service Centre and log in with the email address and password used for the voucher, select My products. Here you will see your registered software serial number and a download link.
Are you absolutely sure you entered your email address correctly on the screen where you entered the voucher code? The fact that you have no products shown on your account and have not received the serial number strongly suggests this, I think. IOW, your serial number has been sent to an email address which may well not exist.
If that is the case, your only possible route to resolve this is to use the Support button in the header of any forum page to contact Magix Sales, explain the situation, and ask if they can help you.