According to facts depicted in the movie, the akshayapathra is located in kumari kandam. But as per my knowledge the kumari kandam sunk below the sea even before the time of Ramayana. I don't see how the akshayapathra would have reached the sunken continent after so many other characters of history using it. Even if the characters of history used the akshayapathra, I don't see how the artifact could have reached the land under the ocean.
I don't think this movie is entirely based on true facts.