I just called amazon customer service and got put through to the download department. He informed me that there was no information put out by anyone else, and no reports for him to see. I told him about the person calling someone that forwarded the request to marketing, and he said he wouldn't have escalated it that way. Instead, he filed a report to send to the Paradox and try to resolve the DLC issue that way, and will follow up with me in a couple of days or if anything's changed.
I've also sent an email via the magicka web page about purchasing through amazon and not receiving a code for the bonus DLC.
Needless to say I was a bit shocked when he told me I was the first to contact them about this issue, esp when I know that some of you have tried to contact amazon about it already. Of course, you may not have gotten to the download deptarment?