“I was saying!”
The only situation where it is appropriate to say this (in such a wording) is when claims are made to you in the style of “why didn’t you warn” (if you warned).
In other cases, it sounds like bullying. Man is so bad because of his own mistake, and here you are still angry. Half of the negative attitude to the situation immediately passes to you.
If a person, even after the mistake did not make the correct conclusions, then - we do not teach, and "I said!" no longer helps.