Liquid damage on a waterproof phone

We own a WATERPROOF Sony Z3. my husband made sure all the ports were properly sealed &put the phone on the top step of a pool for less than 2 mins. later the camera misted up &the speaker and vibration went soft. We sent it away for repairs. Vodacom have assessed it twice and say both times Sony insist it cannot be repaired and does not fall into warranty guidelines. it was returned saying liquid damage - no warranty yet the warranty &user guide clearly states water damage is not covered if the IP rating limitations are exceeded(30+mins in water /1.5m +depths)in our case they were not exceeded. our device should therefore be under warranty. if the advertising for the phone says it can be immersed in water under certain conditions and we put it into water for 2 mins then we should be entitled to a repaired phone or a replacement. We cannot accept that a phone with clearly listed limitations not be under warranty if those limitations were not exceeded. also, vodacom did not even re-assemble it after the first assessment. the phone being returned worse off than when it was sent away is shocking.we cannot even get hold of anyone at Sony for assistance. This is so disappointing.