what you do is take out the control pieces on the door..

there's a THICK black wires that is under the switch. push that in with hand or tools, and have a friend push the roll up button, and most likely it will go back up. i'm guessin , the wires are either loose or stripped.

its doesn't take alot of time, maybe about 5 min to fix...

and if that doesn't work, mostly likely u're master switch is bad..u need to replace