"That that that that man used is wrong," she said. "What did you just say?" "I said that that that that that man had used was wrong." "Oh... Are you all right?" -----
答えの前にヒントです。
第一文は、That "that" that "that man" used と解釈すればわかりやすいです。
さてさて、答えです。
意訳っぽいですが。
「That that that that man used is wrong,」と彼女は言った。 「いま、なんていったの?」 「that that that that man had used was wrong.、と言ったのよ。」 「えー、大丈夫?」