Crab has been molting for 4 months

[EternalTurtle]

I have 3 hermits, and I’m a new owner. (Less than a year of hermit keeping.) All three went down at different times in mid-July. The other two came up for about a month, then went back down. But my third crab, shes the biggest out of them; maybe an inch?, hasn’t come up at all. I’m worried that she’s died, or that the other two have eaten her.