While it is unusual, these things CAN happen. Mounting the hands on their pins is a science in itself: Do you press them on too tightly, they will be damaged themselves, and might even compromise the working of the watch. If you mount them too slightly, they will start to glide on their pins, not showing the accurate time, and, very rarely, might even leave their proper place at all.
Unlike a car mechanic, who has a torque wrench to use a preset force, watch manufacturers, who still do assemble their watches by hand, have to depend on the watchmaker's experience alone for setting the hands. Mass-produced watches are assembled by robots, which also take care automatically for the correct force.
I know that you are not likely to feel better now, but I wanted to make you understanding the problem's sources a bit better, maybe. This should not mean, though, that the assembly was not faulty. However, since it had worked properly for more than two years, one would imagine that the watch assembler's error was so small that it developed into the problem shown only after a considerable time.
I would say that a well-trained watchmaker in your (relative) neighbourhood should be able to correct the problem. Just make sure that he tests the watch for water tightness afterwards.
Regards,
Marcus