They damaged my phone

I handed in my Sony Xperia Z3 because it refused to switch on after taking a pic in the pool (waterproof phone). I heard nothing back for nearly a month and then decided to visit the Bayside store where I handed the phone in. The manager, Eben told me the warranty couldn't be upheld because the handset was bent, which is how water got in to the phone. I then told him that the phone wasn't bent when handed in and they cannot provide proof that it was. I was told on 18 February by Tremaine that she had the phone in front of her and that it wasn't bent - the sim tray was inserted incorrectly and that is why the port wouldn't seal but it's not bent - still no explanation as to how water got in to a waterproof phone.After nearly two months and endless battles to get someone to correspond with me and answer my questions, they are still refusing to repair the phone under warranty and are expecting me to pay for the damages. Yesterday, after I emailed her (I requested her e-mail address many times and never got it so i found it on Google) I got back a report stating that the handset is bent. Can someone please help me sort out this mess. It's been lies after lies