Well since Friday I haven't been able to play GW2. I've fallen into the group of people who bought a HoT cd-key through a 3rd party. My GW2 account is currently suspended. I've already submitted a ticket, received a response, replied back (which they told me a key was invalid), and so far it seems like it's a waiting game for my account to be cleared. Even though I'm still a little worried since they stated that I might not receive a reply back. Some people were lucky and only got the invalid cd-key removed from their account. Others weren't so lucky and are waiting for their account suspension to be lifted. So this will most likely to be a lesson learned for whenever the next expansion pack or next ArenaNet game comes out. It's safer and less of a pain if you just buy directly from ArenaNet. Also, I did talk with the 3rd party vendor's customer service and they removed the seller who sold the invalid cd-keys. It looks like there have been a lot of complaints made on the seller, but hopefully a lot of other people learned the same lesson as me.
Maybe they will sticky the following thread in the future: