How does Telecom Unbind the Primary and Secondary Cards by SMS?

Call the human customer service and send a short message to cancel according to the prompt information given.

You can bring your ID card to the official telecom business hall. Note that it cannot be handled across provinces. If you don't have time to go to the business hall, you'd better call customer service 10000, press 0 to turn to manual service and tell the customer service staff what they need.