Unsatisfied with outcome

I sent a Sony experia in that got a single crack, which happened during the night, while the phone was on the bed. They say it's physical damage, that I don't agree with because, there is not a single mark or scratch on the phone. They want me to pay 1150.00 for repairs or 350.00 if I don't want it repair. I also believe that this is a problem with this phone. <br> Thanks theronda