Your best bet against Ulgamoth is a bulky water type.
I'm afraid I can't remember your team completely, so here's a little count quote from DA's threat list
"This set doesn't have that many counters or checks. Kerudio is at the top of the list with Poliwrath as they resist basically everything this set does apart from the extremely rare Psychic. Poliwrath is also a physical water, something this set hates and can even PHaze with Overhead Throw. Evolution Stone Chansey and Blissey are next on the list but need Toxic or Thunderwave to prevail. Defensive Gyarados and Salamence also works extremely well. High special defensive or Bug/Fire resistant Thick Fat Pokemon like Snorlax and Hariyama are a massive issue which Volcarona really cannot deal with well. Specially Defensive Politoed serves as a good check as it brings in the rain and can Toxic or Encore or just Surf for heavy damage. Faster Scarfers like Terrakion and Garchomp serve as awesome checks as they can even beat it speed wise after a Butterfly Dance and OHKO with Stone Edge. Things like Swift Swimmers in rain are a massive threat to any Volcarona set too. "