I had interview in English first with my future colleague and somebody trained for interviews. Then I had the 2-nd part in German language with my future supervisor and the team lead. A lot of questions about conflicts, delays, and dealing with the team members of diverse cultural background. For customer service position they want to be sure that you are not overeducated and you stay for two years minimum, that you have a high level of social intelligence and you can handle in a correct manner people you don't like or unexpected demands, questions and accusations from customers. Of course they want to be sure that you are computer literate as you will have to use computer all the time.