I can't cancel my downloads.

I've tried to press start, triangle non of that works. I wanted to do some downloads on background so I could still play skate 3 and having new games. But then I realized that the console would be on for too much time so I want to cancel it, but I can't (Even the download icon doesnt show up even though im download stuff). If helps, i've tried to download on zukostore (I know its a shitty ahh store, and I delete it btw) pls help me.