How many days can I keep the SMS off?

The mobile phone number can only be saved for 24 hours when the mobile phone is turned off.

It is also possible that you said that you received the text message for more than three days. For example, during the Spring Festival or some holidays, when the number of short messages is particularly large, and the signal is weak, there will be some short messages delayed, but as you said, three days is rare, and it is common to delay 1 day.