Choosing the right client

I am finishing a Drupal customization job. When I first was offered to do this job, I was reluctant to accept it. I was convinced by a friend. The site at the beginning needed to be localized in 2 languages. Today, the delivery day, we were told the only need one language. WHAT-THE-FUCK?! Getting the site localized was the task that sucked most of my time and now they tell me they don’t need it. Unfortunately I am not managing the contact with the client otherwise they would hear something from me. The 2 bad things are that money I am getting is still the same and they may think everything is alright if you say you need a site in 2 languages and then, weeks later, you say you need just one. Gah. I am really angry now. Surely this teaches me something.