Poor excuses from the advanced repair centre

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. Today it was returned saying liquid damage - no warranty & the phone was not properly re-assembled before being sent back(it was like new when sent away)when reviewing the warranty &user guide it states water damage is not covered if the IP rating limitations are exceeded(30+mins in water it 1.5m +depths)in our case they were not exceeded. our device should therefore be under warranty. It has now been sent back to the advanced repair centre. We cannot accept that a phone with clearly listed limitations not be under warranty if those limitations were not exceeded. also, the phone being returned worse off than when it was sent away is shocking. This phone was purchased in January, it's basically new.