The person who lives above me got off at my floor and came into my apartment by mistake late at night.
この場合、次のような言い方ができますよ。
ーThe person who lives above me got off at my floor and came into my apartment by mistake late at night.
「夜遅く、上の階に住む人が、間違えて私の階で降りて私の部屋に入って来た」
person who lives above me「私の上（の階）に住む人」
to get off at my floor「私の階で降りる」
to come into my apartment「私のマンションやアパートの部屋に入ってくる」
ご参考まで！
カナダ 
