What is the semi-shutdown state?

arrears and semi-downtime means that the user fails to pay the fee within the specified time (the 5th to 25th of each month is our payment period), and our company will stop the user number for semi-downtime on 26th. During the semi-downtime, users can only answer the phone and receive short messages, but can't make phone calls, send short messages, surf the Internet, etc. If the arrears of last month have not been paid off on the 29th, it will enter the state of full shutdown, and the mobile phone number will not be used normally.