I tried looking around and I can't seem to locate any e-mail or contact information for customer service in this confuse em' up you call a site.
Been a member of DDI since launch and just in the past week I've logged in a couple of times to take a look at the new content but seems every time I try to download a article it just goes to the same exact download page but everything is frozen or some such. All I can do is back out. I've been patient and waited a couple of days, hoping it was just a problem with the site but seems other folks are downloading these articles just fine.
The best way to contact CS if you have a problem is to use the "Contact Us" link at the bottom of the page. Once there, use the following set of options to get to the DDI part:
Tried getting to the email us tab you mentioned there but all I get is an untitled page that never loads.
Then you need to go to the thread here, make sure you read the OP and then post your problems in the thread. You should get a response in 2-3 days. Watch the thread so that in case the email gets eaten by your spam filter, you can catch it.