Koichi complained incessantly about the Tofugu employee's JLPT results.
I think Tofugu is, without a doubt, the best of the online Japanese learning tools.
It’s funny that the Japanese word for complaint is pronounced like the English word monk.
A paragraph in writing is what you send someone when you want to submit a complaint. You want to make sure these are in writing, though, otherwise you don't have proof of your complaint. Also, don't make it longer than a paragraph, because that's too long and nobody cares about how you think the shop staff mistreated your dog Fluffy.
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.