You can't send a message if the phone bill is lower than Unicom.

If you have a short message package, you can send short messages as long as your mobile phone is on, but if you don't have a short message package, you can send short messages at 0. 1 yuan, that is, your mobile phone number is on, and the phone bill balance can't be less than 0. 1 yuan. It is recommended to check whether your mobile phone is turned on normally. Not enough traffic? Half a year's traffic is easy to get! The flow is not cleared across months and is valid for half a year. /sAAGl enjoys a 20% discount.