Sometimes when the offender cannot be confronted directly, it is helpful to write out your feelings in a letter which you can either send to him or might decide to just throw away. This allows you to verbalize your feelings, but in written form, which takes the potentially destructive energy out of them.
David did this in some of the Psalms. He even wrote some angry words to God—look at the first part of Psalm 13.
Ps 13:1 How long, O LORD? Will you forget me forever?
How long will you hide your face from me?
Ps 13:2 How long must I wrestle with my thoughts
and every day have sorrow in my heart?
How long will my enemy triumph over me?
Ps 13:3 Look on me and answer, O LORD my God.
Give light to my eyes, or I will sleep in death;
Ps 13:4 my enemy will say, “I have overcome him,”
and my foes will rejoice when I fall.
Ps 13:5 But I trust in your unfailing love;
my heart rejoices in your salvation.
Ps 13:6 I will sing to the LORD,
for he has been good to me.
Have you ever been angry with God (Psalm 13 vs 1-4)? Share your feelings with him. You will then be able to think more clearly about his mercy and love (Psalm 13 vs 5-6), which are always at work behind the scenes.