So I pre-ordered a copy of ME2 and got a code for the Inferno armor. Since this was the first time I had to deal with the whole EA online thing, I had to link up my gamertag and my EA account. Although this service of the site isn't working so I email support, a week or two later I finally get a reply and the guy was nice enough to link the accounts for me.
 
Now I finally redeem the Inferno armor (which looks pretty bad), but for some reason now the damn Cerberus network thing is no longer working and keeps asking me to buy a new one!
 
Anyone else running into similar problems?

No problems for me

masseffect.com > Redeem Code
 
If you don't have an account I guess you'll have to make one, not having a BioWare account though... that's like not having a Battle.net account.

The first thing that popped up when I started the game was "Redeem Cerberus code." I entered it, and downloaded the dlc and went on my way to playing the game.
 
It even shows you how to do so on the cerberus card. I don't get why so many people are having problems...

It's not hard at all. masseffect.com and it's right there glaring in front of you. Hows that hard?

You should try the Bioware Forums, I've heard of other people experiencing a similar problem with the cards.
 
And yes the difficulty is that you have to redeem certain DLC through another website as opposed to on the xbox where as sometimes it tells you to go redeem it on xbox or something.