но он не стал

but he wouldn't

→ но
phrase Rare #44,556
but he wouldn't Usually followed by an infinitive: не стал слушать means “wouldn't listen” or “refused to listen.” When used alone, the action is understood from context.
RU: Я попросила его помочь, но он не стал.
EN: I asked him to help, but he wouldn't.

Я пыталась сказать это папе, но он не стал меня слушать.

I tried to tell my dad, but he wouldn’t listen to me.

— Двойная страховка (1944)

Я хотел поговорить с Томом, но он не стал меня слушать.

I wanted to talk to Tom, but he wouldn’t listen to me.

Но он не стал.

But he didn't.

— Ла-Ла Ленд (2016)