There are two similar words of opposite meaning.
Reproach - criticize
Reproach - to remake friends
As spelled, you appear to be looking at the first meaning which would be an act of criticizing.
Reproach means to criticize or express disapproval. "Reproachment" is not in most dictionaries but there are some miscellaneous references in literature and other written sources. Although it doesn't mean too much in the scheme of things, spell check doesn't recognize it.