If the Mayan calendar is so acurate why was it wrong about 2000 and why does it have another date to die?

The idea that the Mayan calendar predicted the end of the world in 2000 is a misconception. The Mayan Long Count calendar simply marked the end of a cycle, not the end of the world. The December 21, 2012 date associated with the Mayan calendar was misconstrued as the end of the world, but the calendar itself does not predict the end of existence.