It already happened twice to me that a specific class / job I'm playing suddenly resets the quests to lvl 1.
It happened to my archer when 3.1 was released, and now to my marauder when last patch was released.
Every single time this happens, I have to start from the initial lvl 1 quest needed to unlock the class, and then go through the lvl 5-10-15 and so on until I catch up with my current class level.

When it happened on archer, I opened a ticket for NO reply for an entire week.

Bad support isn't it?