3rd time unlucky

I have had a z3 for about 8 months now and have decided to take advantage on the waterproofing feature or as they advertise. This is the third time now that i have done this and the 3rd time that my phone has acted up. The first two times I was not able to use it for about 2 days after that. The third time it has completely stopped working. I follow the steps, i close the seals, i do not use it for more than 30 minutes nor do i go close to a meter under the water. It has been three days now and i have to now send this in which as i know with cellphones is going to take weeks in which i will now be without a phone. The phone goes on, i can hear when a message come but the screen does not come on and if it does, it is not at all responsive. I have had such high hopes for Sony as the phone itself has been one of my favourites however it is advertised as a waterproof and when i use it as that, it should then work. I am extremely annoyed with this and advise that people be careful when using their z3 or buying one for that reason.