Conyac で依頼された翻訳結果を公開

I am a Japanese customer who started using your services early this year to import merchandises. The number of transactions I've made is only about 10 so far. I may be a small customer, but there is a reason why I'm writing to you.
I have experienced some excellent services you provided in the past. I've thanked the person in charge many times. I still want to trust your business. HOWEVER, the last two times, I have experienced extremely malice pranks. This may not be anything so unusual in the U.S.; but in Japan, such pranks are entirely unthinkable.

You may think I cannot assert that the pranks were done by employee(s) at your company; however, by process of elimination, this is the only conclusion I reached. I have already requested this to you, but I repeat myself: please provide proper training to all of your employees. I apologize if I sounded rude to you.