expression
I don't give a damn; that's got nothing to do with me
Colloquial, dismissive expression used to show complete indifference or refusal to care about something. Often carries a defiant or confrontational tone.
そんなの知ったことか。
I don't give a damn about that.
お前の都合なんて知ったことか。
Like I care about your convenience.
知らない is a neutral statement of not knowing; 知ったことか is a strong, dismissive expression of indifference.
どうでもいい expresses that something doesn't matter, but is less confrontational than 知ったことか.
From 知る (to know) in the past tense + こと (thing) + か (question marker), literally 'Is it something I know?' or 'Do I know that?', used rhetorically to mean 'I don't care'.