Maintenance for the week of March 16:
• [COMPLETE] ESO Store and Account System for maintenance – March 18, 6:00AM EDT (10:00 UTC) - 4:00PM EDT (20:00 UTC)
We actually just posted an update about this (which you can find here).
There is currently an issue with the achievements not unlocking on your Xbox Live account. We'll provide an update in the thread linked above once it's been fixed.