다가 망하다

tried X and it backfired

-다가 marks a course of action that got interrupted by what follows, and 망하다 is failing, going under, being ruined. 사업에 덤비다가 망했다 'jumped into business and went bust'; 설레발 치다가 망한 적 'times I got ahead of myself and it fell apart'. With a past tense before it — 샀다가 망한, 그랬다가 망하면 — it means having done the thing and then coming to grief.