Welcome to the community! I'm sorry to understand that you're having issues with your landline phone.
Can you tell me what happens when you try to call the landline from another phone? Does the call fail or ring out (if you know)?
Also do you know if it is only certain numbers that are unable to get to through? Such as mobiles or other landline numbers?
I've got an engineer booked to come out now.
Glad that you could get an engineer booked to get your issue resolved. Please let us know how the appointment goes Jad02.