Land registration queries

There was a piece of land from East to West in length and belong to a person who has four children A pandit, B pandit, C pandit and D pandit after his death they distribute the land among themselves in sequence from East to West. After some time Mr. A pandit died and his wife sold her half of the share to Me from East and half to Mr. B pandit from West, after some years B pandit also died and he has four daughters only. Later one of them sold her share of land to Me from the East side. After that her all three sisters supported her to sale the remaining land to Me and they sign as evidence on the land registry documents. Subsequently when I went to occupy the land I found that the share of Mr. B pandit which I had bought from his daughters, has been sold by Mr. D pandit to Mr. Z singh. Since the legal share of Mr. D pandit was in West side then how he can sold the land from East side if Mr. B pandit has already bought a piece of land of Mr. A pandit adjacent to his land in East side.