Somebody sent me a letter that included this sentence
Извини, это я сделала не случайно.
I looked up случайно and it had the definition
accidentally, by accident, casually, by chance
So I assumed не случайно meant not accidentally, i.e. on purpose. But the person who wrote me said не случайно means on accident.
Does the negation of the word really mean the same thing, or am I missing something?