Send a text message at 189. Why is the prompt unsuccessful?

There is always a question to remind people to enter a contact when sending a short message with 189. Please check whether the contact format entered in the contact column of the receiving mobile phone is correct (SMS can be sent to the mobile phone users of China Telecom, China Unicom and China Mobile, and the mobile phones are separated by English commas). Click on "official website" Customer Service 2 17 below for more service offers.