2 Answers

When the push down lever hits the bottom it pushes another little lever which makes contact with the positive and negative terminals. over time, these terminals get ever so slightly bent, especially if you start pushing the lever down hard. what you have to do is take the toaster apart, get to the positive and negative terminals and pinch back into shape with some pliers. you should understand once you look at it. Then put back together. if it doesn't work then it's likely a component has gone so, unless you have a multi-meter and a soldering iron I wouldn't suggest doing this.

Oh yeah, unplug it before you do anything.

it's stuck huh? hmmm.... try pulling it up with something sturdy on both sides. when it pops into place, you got it fixed