On the left of my screen, there is "Your Control Panel".

Click on "List Your Subscriptions". You will then see a list of all your subscriptions.

You can click on the boxes on the right side of the screen for each subscription you want to delete. When you have checked all you wish to delete, go to the bottom of the screen where the pull down menu is and choose "Delete Subscriptions" and hit Go.

That should do it.