Someone wrote and said that their child was ill and moved in with parent. However the child's accommodation was empty and council tax and rent still had to be paid. I believe that landlords don't like their property to be left empty and may invalidate insurance if left empty over a certain time period. Could you contact the landlord and ask for the tenancy to end? It seems unsustainable to be paying for something that you are not using. Someone else may be able to offer some further suggestions