Hi there! It sounds like you're having some trouble reaching your friend, and I’m here to help you get that sorted out.

First, can you confirm if the issue happens with just calls and texts, or is it also affecting any other apps you might use for messaging, like WhatsApp, iMessage, etc.? Also, have you recently updated your iPhone to the latest iOS, or have you checked for any potential network issues?

In the meantime, let's try a couple of basic troubleshooting steps:

1. Restart Your iPhone: Hold down the power button until you see the "slide to power off" option, slide it, then once it’s off, press the power button again to turn it back on.

2. Check Airplane Mode: Make sure Airplane Mode is turned off. You can check this by swiping down from the top right corner of your screen to access Control Center and looking for the airplane icon.

3. Re-add Your Friend's Contact: Sometimes, a contact might have an error. Try deleting your friend's contact and re-adding it:
- Go to your Contacts app, find your friend's name, and delete it.
- After that, restart your phone as mentioned, then add their contact back manually.

4. Network Settings Reset (if the issue persists):
- Go to Settings > General > Transfer or Reset iPhone > Reset > Reset Network Settings. Keep in mind that this will erase saved Wi-Fi passwords, so you will need to reconnect to your Wi-Fi network afterward.

Give these steps a try, and let me know how it goes. If the issue is still not resolved, we can dive deeper into further troubleshooting! Are you satisfied with the initial steps I've provided?