Answer:
Tell the manager and he will direct the complaint to the employees about the type of issue the customer has
Explanation:
According to the rules, you cannot do anything except for saying: "I am sorry about that, ma'am/sir. If you have any complaints, you can go to the customer service and they will take action immediately"
And then you just need tow wait for the consequences, like, for example, the manager can talk to all of you, warn, and can also terminate. Sad story with terminating, but usually you will end p receiving a lower paycheck