Two phone interviews. The first is pretty informal, they make sure you are aware that the position is a call center position, and provide you with additional information about the job. There is a few basic questions about your previous experience.
Second phone interview is more formal. Many "Tell me about a situation when you encountered ---, and how did you handle it. " Most of these are teamwork or customer service oriented.
A face to face interview may be given after this second phone interview