Why do you receive missed messages from Guangdong call manager many times?

Using Guangdong call housekeeper service, I received missed message reminder messages many times. Reason: 1. If you dial the same number of the user's mobile phone for many times, you will be called to the call manager system, and a number of missed messages will be sent to the called user, but the time of the missed messages is different. 2. If you are in an abnormal state (shutdown, no signal, etc.). ), the SMS center will resend the message several times within 48 hours until you receive the missed message, so you may repeatedly receive the missed message with the same content after turning on your mobile phone or having a signal.