"Never really worked" is a bit vague. Can you provide some detail please.
Do you have a dial tone? Can you make outgoing calls? Can you receive incoming calls? When you dial 174 does the automated voice report being attached to your phone number or some strange number you've never heard of? Have you tried a different phone in the socket?
No dialling tone no nothing and on the phone I have it says line in use.
Don't have another socket.
It looks like you'll need an engineer visit. You can wait around here for a member of the Forum Team to turn up but that could take several days. Alternatively if you have access to another phone, call VM on 0345 454 1111.