What pokemon do you have?
I don't remember what level the pokemon are at that time but if you're losing to totem pokémon then you're probably underleved. Just grind a bit around tapu village.
If the problem is the sos pokemon, then just paralyze mimikyu, so it can't call for help, and target it only if there is already an sos pokemon on the feild. Once the totem pokemon dies, i don't think that the sos pokemon will call for help.