Card Rulings talk:Cursed Seal of the Forbidden Spell

my friends play cursed seal of the forbidden spell like this example: I play pot of greed, my opponent activates cursed seal of the forbidden spell and discards fissure. i know i can't activate pot of greed but can i activate fissure? my friends play it so that i can't activate the played spell card and the discarded spell card. please clarify this for me. thank you.