Out going calls

[Chris419]

We go out of our house at 7am for work.  I hadn't taken much notice of our bill,  having checked it this month I noticed strange numbers being called. On checking the Times of the calls they are being made in the mornings when nobody is in the house to make them. How can this happen? It's one or two calls per day at 27pence per call, may not sound much but it adds up over a few months. We have been with bt since april this year. 

How can we stop these calls? 

Chris.

[imjolly]

check number by dialling 17070 and your number should be read back to you

could it be a house alarm checking in