What can i do about my Laptop?

I recently sent my laptop off for repairs, its a Toshiba btw. They expected me to pack it myself, instead of sending me a package, so i did and made sure it was safe and secure. I get a call the next week saying the laptop screen has been cracked because of insufficent packaging, and expected me to pay 286 pounds to repair the damage. It was not insufficently packaged, and the laptop only cost 320 pounds. So i decided to have laptop back with the repairs done by the warranty finished. Upon opening the box that it had been send back in, the packaging that they had returned it in was flimsy cardboard and a sheet of thin plastic. Could anyone tell me what i can do now to either (a) get a repair of the screen or (b) to have my money back for the computer.