imessage

Hey there, and welcome to Apple Support Communities sandrine229,

We can certainly understand your concern and can help provide some insight.

We recommend checking out these step on what to do if you are having issues sending or receiving iMessages.

" If you have issues with Messages after you set up a new device

If you experience issues like conversations in Messages showing up as separate threads or sent messages appearing as green message bubbles instead of blue message bubbles when you set up a new device, update your settings using the following steps:

1. Update your device to the latest version of iOS or iPadOS if needed.
2. In the Settings app, tap Cellular. Make sure that your phone line is turned on. If you use multiple SIMs, make sure that the phone number you want to use is selected and turned on.
3. In the Settings app, tap Messages. Turn iMessage off and then back on.
4. Tap Send & Receive.
5. Tap the phone number that you want to use with Messages.

If you have issues when you try to receive a FaceTime call after you set up a new device, you can also update your FaceTime settings.

If you see a red exclamation point

If you try to send a message and you see  with an alert that says Not Delivered, follow these steps:

1. Check your network connection.
2. Tap , then tap Try Again.
3. If you still can’t send the message, tap , then tap Send as Text Message. Messaging rates may apply. Contact your carrier for more information.

You can set up Messages so that it automatically tries to send messages as an SMS when iMessage isn't available. Go to Settings > Messages, and turn on Send as SMS. "

For additional information, check out this link: If you can't send or receive messages on your iPhone or iPad - Apple Support

These steps will help ensure your device is working with ease and can fix common issues like the ones you’re experiencing.

Kindest regards!