IMO- they all killed each other and you are left with the survivers and the bill.
Their was a artice in aquarium mag that said hermits are found in sand beds not reefs. It recomended 1 or 2 hermits for every 100 gallons.
I have 1 in my 100 gallon. I can't tell you how many I put in there at different times. They all kill each other. I learned my lesson the hard way.
I have a bunch of different snails, a cuc, 2 cleaner shrimp, a serpant star, a urchin and 1 hermit for my cleanup crew. I also have a spotted brittlse tooth tang who is allways pecking at the sand, he keeps it clean for me.
Sorry for the loss. IMO, I would try other things for clean up and not add more hermits.
HTH