According to a recent announcement by ArenaNet, it would appear that first party sales of Guild Wars 2 has been officially suspended in an effort to ensure the quality of game play for the current playerbase. For a better explanation, read the statement below made by ArenaNet on their facebook page.
Ensuring the best possible play experience for our fans is our highest priority. We’ve said before that we would be willing to temporarily disable first-party digital sales if we felt our high player concurrency may compromise player experiences. We have now reached that point. Effective immediately we have disabled sales via buy.guildwars2.com. To be clear, box and digital sales are still available via our retail partners. We are tracking our concurrency closely while expanding our infrastructure. We’ll re-enable first-party digital sales as soon as we feel that we can do so safely. ~RB2
Many players will find comfort in the fact that the developer chose to stabilize the game rather than oversell it and cause the player experience to degrade while they iron out the current list of pressing issues.