Armor stand with armors disappered and iron farm villagers also.

I had 5 armor stands with full set of diamond and iron armor set are disappear. Armor stand were placed near 30 blocks to iron farm. And it happens when i was at iron farm and filling the land with slabs, and i need more slab to fill the land, for that i moved to my stirage room which is 70-80 blocks away from my iron farm, and when i came back i found there is no armor stand and no armors. And all villagers were disappeared.