There's nothing to be done, you're right.
'Niente da fare' — NIEN-te da FA-re. 'Niente' is two syllables: nyen-te. Stress on first syllable.
Use when you concede a point after resisting — 'non c'è niente da fare' signals reluctant but genuine acceptance that the other person is right.
'Non c'è niente da fare' (there's nothing to be done) normally means 'it's hopeless' or 'nothing can be done'. In this context, it means there's no further argument to be made — the other person has won the debate. A kind of reluctant surrender.
Devo ammettere che avevi ragione.
I must admit you were right.
Retrospective concession — you're admitting they were right from the start
Mi hai convinto.
You've convinced me.
Direct — signals the other person's argument successfully changed your mind
Non posso contestare questi fatti.
I cannot contest these facts.
Specific to factual disagreements — the evidence has settled the matter
In Italian debate culture, admitting you were wrong ('avevi ragione') after a good argument is respected. 'Non importa chi ha ragione' (it doesn't matter who's right) is a magnanimous move that refocuses attention from winning to problem-solving — valued in collaborative contexts.