Welcome to the Community!
Really sorry to hear you're having trouble with your landline.
I've run diagnostics on the line and everything is looking clear on this end. Can you try using another handset in the socket? This is just top make sure the handset isn't causing the fault.
Let me know if you don't have a spare handset and I'll arrange for a technician to check it out.
Tech fan? Have you read our Digital life blog yet? Check it out