How you can handle a complain from a bad tempered customer?

Listen first and try to answer in a politely manner. Never contradict at the same time the bad tempered customer.

1.      1.  Listen carefully and intensively to your customer.

2.     2.   Try to understand him, his feelings and the reason why he is unsatisfied. Did you deliver poor quality? Or did he have different expectations?

3.      3.  Try to find a good solution which satisfies you and your customer together in discussion with your customer (i.e. fixing a defect, clarify misunderstanding)

answer should be high quality of service :)