効果 こうか抜群 ばつぐんじゃなかったです
kōkabatsugunjanakattadesu

Noun
Desu Copula
na-Adjective
no-Adjective

The polite, past negative form of 効果抜群

1. It wasn't effective.; It didn't work well.

Past/Perfective
Negative
Polite
Casual Register