I was unable to find Spirit Channeler Emissary in the class list when I added the proper source (Pathfinder Roleplaying Game Adventurer’s Guide ) and even double checked with the requirements fulfilled.
Well, I don’t see any Spirit Channeler Emissary, but I do see Rivethun Emissary. Which seems to have spirit stuff:
Enhanced Spirit Animal
I’m going to make an educated guess and figure you consulted d20pfsrd which cannot use the proper class name and since you used the incorrect name you couldn’t find the class.
Anyways, closing as this.
OP looking for wrong class name. Closed.