I recently clicked " complete my season" but itunes is now trying to download ALL the episodes I have already purchased as well . This uses up my expensive internet connection and I don't want previous episodes as I already have paid for them.

As said above, I recently clicked "complete my season" on a particular Tv show. BUT itunes is now tring to download ALL the previous episodes I have already purhased which I do not want. I only want the next and new episodes of the series. By trying to download previous episodes, I am using up my expensice internet allowance. How can I prevent this from happeningand just get the NEW epiosodes ?