Hi Carley.
My phone is connected to a master socket on the wall as it has always been. Its VM socket installed when I moved in.
Nothing else is connected to that socket.
I have checked my phone and its all OK. I can now call it from my mobile phone which I couldn't do 2 hours ago.
I don't have another landline phone in the house im afraid. My actual landline phone does have \BT logo on it but I have had it for several years.
Does this help?