false advertising and poor service

i am fully aware that the Sony Z1 compact is a waterproof phone as stated by Sony themselves. i also am fully aware of all the precautionary measures that needs to be put in place. My Sony Z1 is 9 months old, all ports are always closed and never used beside the charging port which gets used daily. I decided to put the phone in water 10cm deep if that even, took a 10sec video, watched the video afterwards and then took some photos and looked at the photos thereafter. All ports were closed for sure. after 5min the phone shut down and i put it back on thereafter shut down again and never came back on. Sony and MTN are taking absolutely no responsibility. I believe this is false advertising of an expensive product and should be taken to further authority<br> i will never recommend a Sony product to anyone.