Sub-tenancy curtain issue

Chrissy asks:
(updated on Friday, February 20th 2015)

Hi there. I am flatting and renting two bedrooms with a couple who rent the house off their parents (whom are the owners) but I don't have my name on any agreement. I have given notice to my flatmates that I will be shifting out and they have advised me I am required before to pay over $250 for the curtains to be dry cleaned as they apparently had them done before I moved into that room. From my understanding this should not be expected of me as the curtains are a chattel, I always believed it was the landlords responsibility for household maintenance. They had some mould on them when I went into the room and over winter it has become a little worse. The windows are not double glazed so there was a lot of moisture and mildew on the windows. I would understand if I had caused any damage or marked them in some way but that is not the case. This is just general mould that can't be avoided. Advice would be great please.