"But they rejected me, because they say that in those woods was never seen a single wolf ever." - Is this use of never ever correct?
It's difficult to comment on how correct it is because the entire sentence sounds very poetic and antiquated. Expressions like "was never seen" are not in common usage in modern English however it is commonly heard in movies about the early 1900's and so. If someone made this statement in everyday speech, I would assume he was quoting some old literature and consequently, the validity of it loses relevance.
If the statement was made in earnest, I would assume he really wanted to emphasize "never". I do not think it is technically correct in modern English though and it wouldn't naturally be comprehensible.