If this exercise is testing the causative form in the past simple tense, the missing verb should be in the bare infinitive form, for example: They made her wait too long in the room. They made her stay too long in the room. They made her sit too long in the room.

Your sentence is not complete as it is. It appears that the elipsis (... the three dots) is taking the place of a missing word or words. The most logical word I can suggest is the word, "wait". "They made her wait too long in the room." That would make it a complete sentence and, yes, it is simple past tense.

So it's not use v2(waited)?