You are not required to be an expert on the organisation or role, but a genuine interest and basic understanding is expected. If you are working with a recruitment consultant then they should be able to provide you with extra details and assist with preparation.

In addition, look for and use press releases, corporate and social websites. Ring the call centre to see how they handle your call: do they offer 'up-sell', 'cross-sell', how was the service? Read the job description to prepare for this question, a few key facts or some knowledge show a genuine interest and commercial awareness.