Why has Degrassi TNG been taken off Itunes Canada?

I have been purchasing these gradually, even though I have the dvds I purchased seasons 13 and 14 as they have not been released but now I have seen all the older seasons are no longer available to buy. Does anyone know why or how to find out if they will return. I have asked itunes but they said to contact the media company but I do not know who distributes it? Many thanks