I've had exactly the same!!! My landline has been making calls.. best thing is I dont even have a house phone and havent for 3 years! I want to know how phone calls have been made when I have no phone to make calls on!
First I found out was this morning when an engineer turned up at my house when I was at work and told me he was fixing the phone line as my line had been calling 112!
I want virgin to explain how that is physically possible when its physically impossible.