Эй, i don't know if it happened to someone else but it's so annoying, the sims that i created were lost?

Here's it. I created sims and after a few days they became lost. And other sims continue their life like they haven't even been exist. Although i can see them in the family дерево their own parents even don't remember them ?? If someone knew anything about it and would help me i'd be so glad. Thank Ты !!