Why is it we do not see angels and prophets anymore?

In the time of Adam, God Almighty, JEHOVAH, spoke to perfect Adam, who was aware that he along with all else came into existence, BECAUSE of God. Evidently, man was to remain mortal, since, the test of obedience, had DEATH or NON-EXISTENCE as its penalty.

As a result of a rebel spirit who made himself a Resister or Adversary [Satan], this penalty was served on Adam [and by extension ALL of mankind]. But, Jehovah, stated a way out as early as Genesis 3:15, and God has progressively revealed through prophets and faithful angels, UPDATES as regards God's means of achieving a RECONCILIATION of ALL things to Himself.

Since the Chief Agent of Salvation of obedient members of MANKIND has CONQUERED, i.e. God's Word, was SENT as a perfect human [equivalent to the COST of disobedience a PERFECT life (Adam, as family head 1 Corinthians 11:3)].

Now, with the convening of the Mosaic covenant, Moses, served as the mediator, a priestly class was assigned, to carry out the function of mediators with JEHOVAH, offering sacrifices first for themselves, then for the people, for FORGIVENESS of sins.

However, Jesus the Christ [anointed One], the Son of God, was not only a Prophet like Moses [Deuteronomy 18:18-19; Acts 3:22, 23], and Mediator of a New Covenant [Jeremiah 31:31- 34; Hebrews 10:1- 18], BUT, also High Priest forever [Psalm 110:4; Hebrews 6:20; 8:1, 2]. 

So, we approach God, through, Jesus, as High Priest, forever, He being put to death, as an obedient faithful PERFECT man, BUT, being raised as an IMMORTAL Spirit [1 Corinthians 15:45 to 57].

Therefore, God, does not need to correspond with sinful mankind DIRECTLY anymore since God's MEANS of SALVATION has ACCOMPLISHED His earthly assignment with SUCCESS.

When we communicate with God, however, we do so through Jesus, the Christ.