Service recovery is similar to the traditional notion of the customer is always right whereby you don't concern yourself with the validity of a customer's complaint but rather focus on making the customer happy again.Next read: Service Recovery Paradox
Be respectful, courteous, professional and patient.
Listen with intent to understand the problem.
Offer sincere apologies.
Sympathize and work to make the customer feel better.
Adapt your communication style and approach to the customer e.g. logical vs emotional customers.
Communicate the steps you will take to resolve the problem.
Investigate the problem thoroughly.
Explain why the problem happened without making excuses.
Be transparent and avoid needless secrecy.
Make it right – try to resolve the problem from the perspective of the customer.
Offer prompt and frequent communications until resolution is achieved.
Keep promises and do what you say you will do.
Keep the customer updated if there is a delay.
Show appreciation to the customer for things like patience.
Demonstrate that you will use the customer's feedback to improve in future.
Ask if there is anything more you can do.
Ask if the customer is now satisfied.