Landline constantly ringing

My landline has developed a fault today where it make an odd disjointed ringing sound and when it is answered, there is no one there. It is then repeated a few seconds later. I am unable to make outgoing calls and when I call it from my mobile I get a message that it is unavailable.

I have tried the troubleshooting steps, with the exception of a different phone as I only have the one, including plugging direct into the master socket. But nothing resolves the issue.

For confirmation, this is a phone with a wall socket rather than connected to the hub.

Can I make arrangements to get an engineer to look at this as the online help doesn't give me an option to raise a fault, it just says the service status is good?