Which pack are you referring to, some mod packs such as Skyfactory also require you to join their team as well as the island. I believe there is a sign in spawn explaining the commands. It should be something like /TF invite (insertnamehere) as SF4 uses together forever to track advancements.
HElp in stoneblock 2 i used balanced clay i get the number of emc and 1 min after i have 0 EMC what is this
Did you change dimensions? A visual bug sometimes occurs showing you have 0 EMC you can log off and on and it will magically reappear. Also don't hijack another person's thread it can cause your issue to be unresolved.