My printed edition of The Oxford English Dictionary is the one published in the 1980s...it does not - as you say - contain the word 'prepone'. On the other hand, the online edition does; it does not, however, refer to it as 'Indian' though some quotes are India-related. It offers both meanings.
The word does, indeed, seem to have effectively disappeared from British English for several centuries. But one of the dictionary's quotations - dating from the 1940s - talks of how Milton 'preponed'...ie put back...Christ's kingship to a time before the world even existed!
To be honest, I am unsure whether there has been a more recent printed edition of the dictionary than mine and therefore cannot say whether the word appears there or not.