i cant delete mobs with command on my server

Hello, I created a mod in which there are about 20 mobs, I made them all of the "monster" type and they spawn at night or in dark places, I added this mod to the server, the problem is that when I write /mobskill it works on all the mobs from any mods, but not from my mod. That is, they have filled the spawn and arena, and I cannot register a mobskill, it does not apply to them. I think that the ban on spawn in the world will also not work for them. What can I do? how to solve this? This is a very big problem for the server