Master Villagers Despawned in my locked house

Hi Team,

I had 5 villagers in my house at their stations in minecarts, in locked house.

I was in my cave spider spawner about 30blocks away, apparently my spawn point was on top of a cave spider spawner. I came back to house to find them all gone, not in the area around my house or anywhere. they just despawned. 

Please help !!

Thankyou.