Sony Z3 water resistant ... but maybe not !

I upgraded my contract with Telkom to a Z3 Sony phone on 15 January 2016. The device was used in the water as it was supposed to be water resistant... A few days later it stopped charging ... It was sent to the Telkom store almost a month ago. Now I get told that it is liquid damaged, the device cannot be repaired and there is nothing they can do as liquid went in through the port. Even after, explaining to them that we took all the necessary precautions, they will not hear that the product could have a defect ... If the liquid went into the device through a closed port then what does that mean ! This is supposed to be a brand new device which was with Telkom more than it was with me ... <br>