Number incorrect

[WDM1]

Trying to call my mother and getting a message saying the number is incorrect? 
she is elderly and on her own so needs the landline

System says no problems in her postcode 

[jpeg1]

Have you tried calling from a different network? If that doesn't connect either then call VM support. 

[Matthew_ML]

Hey WDM1, thank you for reaching out and I am so sorry to hear this.

As mentioned below did you try another number at all?