I don't understand the grammar and meaning of this sentence.
To say that I was moved to tears just doesn't do this act service.
What does 'do this act service' mean?
The whole context:
If the sentence was recast and the word "service" was replaced by ** justice**, I think the meaning would be more apparent.
To say that I was moved to tears doesn't do justice to this act.
Better would be: To say that I was moved to tears doesn't do this act justice.
From Cambridge online: to treat someone or something in a way that is fair and shows their or its true qualities:
This postcard doesn't do justice to the wonderful scenery.