Has anyone received this message? Last Line No Longer Available Do you want to call with one of your remaining lines?

There is a difference between "Last Used" and "Always Use"

"Last Used" : This is waht the Contact has used for contacting you. You can immediately call back from the same number where the call was received from the Phone App > Recents Tab

"Always Use" : This is what you want to use while making a call. Open the Contacts App and Open a Contact and Tap Call. Now it will use your default number.

Normally...

Watch the GIF below to change the Voice line. This has to be done each time you receive a call and want to call back from another line other than through which it was received.

This user has a solution --> Last Line No Longer Available on iPhone - Apple Community

However, the feature on an iPhone is as follows based on the way you are trying to call.

Watch the GIF below to change the Voice line. This has to be done each time you receive a call and want to call back from another line other than through which it was received.

Alternatively, you may change the Voice line to be used under Contacts. And dial using contacts and not using the Recent call list.

While making a fresh call using dial pad.

Error messages on iPhones usually provide specific information about the problem or issue encountered. They may include error codes or descriptions that help identify the nature of the problem, such as connection issues, software conflicts, or hardware malfunctions. These error messages are designed to provide guidance on how to resolve the problem or seek further assistance.

If you encounter an unfamiliar error message on your iPhone, it is recommended to take note of the exact wording and consider the context in which it appears. You can then search for the specific error message online or contact Apple support directly for assistance. Providing additional details about the error message could help in providing a more accurate explanation or potential solutions.