It appears that this entire section beginning with verse 1 in chap 33 is a discourse by Elihu, one of Job's comforters and during this discourse one of the things he touches on is how God communicates with humankind to save them form the ravages of a hazardous afterlife in what is called the "pit".
He already alluded to two of these ways prior to that part of Chap 33 that you quote. First there are "visions" [vss 15-17] then are "afflictions" [vss 19-22] and now in this section he introduces a third. This is a "malekh" which can be translated as "angel" or "messenger" and who acts as mediator. The identity of this mediator is not discussed, except to say that he would be "one among a thousand" or a very rare person indeed. However this may have another meaning. According to the New Bible Commentary this "angel" or "messenger" being "one in a thousand" may also mean that God has several of these ministering angels of mercy.
This messenger does the following:
1 "reminds the man what is right for him" [23]
2 "mediates and says [to God]: be garcious to him and deliver him from the pit" [24]
3 " finds a ransom for him" [24]
4 This messenger pleads with God that the man be returned to good health. [25]
As a result of this ministration the person is healed, prays to God, and is accepted by God [26]
He repents [27, 28]
Vs 29 is problemactic. The words "two, three, times" are idiomatic and could either be literal or metaphorical:
1 If literal it would refer to the three means that Elihu has discussed about how God communicates: Visions, illness, an angel.
2 Or it may simply mean oftentimes [See NASB, NJB] and that God oftentimes attempts to get the person to be reconciled to God.
The upshot is that the man who responds submissively to God's dealings with him regains good health and joy.