You need to rehearse some role plays as they are quite frequently asked for in the interview for call centers.

The focus of this particular role play should be on:

1. Listening carefully to the customer.

2. Apologizing and empathizing with them.

3. Re-iterating and confirming your understanding of their problem

4. Offering a solution and confirming if they are happy with this.

5. Thanking the customer for bringing the issue to knowledge

6. Taking the required steps as promised to the customer.

The key attributes of your personality that show off here are - problem solving, empathetic, good communication, calm under pressure, genuine interest in customer satisfaction, result oriented.