Sony Xperia not Waterproof

On 8 August 2014 I upgraded my contract to the new Sony Experia Z1 Compact Reason I got this phone is because it was advertised as a waterproof phone.On the 25 December 2014 on holiday the phone touch screen did not want to work. My wife was taking n photo of me coming down a waterslide and water splashed over the phone.I took the phone to Vodacom for repairs were they first informed me the phone is not under warranty on their system. Now how is that possible the phone was only 4 Months old and it got a 1Year manufacturer warranty. They send the phone in for repairs and I received it back as unable to repair due to liquid damage and they claim that I don't have a warranty on the phone as it was ceased. When asked but the phone is a waterproof phone they claim I did not close the side cover .This is just a convenience excuse as I always make sure the cover is closed after charging. The phone also comes up with a warning message to close the cover to remind a person to close it every time you unplug the charger. <br> Bottom line this phone is a waterproof phone and I did close the cover and it was not even in the water the water just splashed over it