What is the business of hanging up SMS? How to open and cancel?

"Hang-up SMS" service is an active push service for enterprise SMS advertisements. After an enterprise's telecom fixed telephone (telecom mobile phone) applies for this service, it can easily publish short message advertisements according to this number. When the caller dials this number and hangs up, the "On-hook SMS" service system will extract different SMS advertisements set at this number and send them to the caller in real time. The terminal receiving SMS advertisements can be a telecom mobile terminal, or a mobile terminal of operators such as China Mobile and China Unicom. Customers can handle orders, changes, renewal, cancellation, cancellation and other businesses at the business front desk or contact the account manager at home. When handling, they must ensure that the customer's name and official seal (ID card) are the same as those of the payer, fill in the customer registration form, the company customer must affix the official seal, and the agent must show the original ID card. Individual customers need to show the original ID card. For more service benefits, click on "official website" customer service 222 below to answer your questions.