"Почему ты меня не дождался?" There is no special variant of the verb "wait" to express the "до" part of "дождаться". We could simply use the word "wait". Therefore, we would say, "Why didn't you wait for me?" If we had to say something like, "Я тебя ждал, но не дождался", we would use an entirely different construction such as, "I waited for you, but I had to leave." Sorry I can't help you with the отработать question.

Нет, здесь нет предпрошедшего действия, а есть законченное действие в прошлом ("не дождался"), поэтому его нужно поставить в Past Simple.

1.Why didn't you wait till I came? 2. After graduation from the university he has to work for the company for three years.

1 why didn't you keep waiting till my arrival? 2 he must spend three years working in the company after he finishes the university.

то есть: why hadn`t you waited for me?