Does anyone know how to remove Lilliput 7" monitor from it's case/sleeve? Is there a key or something?

I had the radio/monitor installed by a 3rd party and now I have to remove it and return it to Liliput (gears melted and screen won't open). I've got all the wires removed but now cannot get the unit out of the case and wasn't sure what I'm missing. I'm guessing there's a key or something?

Thanks,

Rookie