Water Damage on Claimed waterproof phone

My Sony Experia Z1 stopped working 5 days after using it in the pool, with all the covers closed. I have sent it through my service provider,Vodacom who have been extremely helpful, to Sony JHB to have it fixed. They claim it is beyond economical repair as it had water damage and as such wont fix it.<br> This is now the 3rd time time I will request Vodacom to send it back, as I feel it is wholly unacceptable for a manufacturer to make false promises and refuse to rectify them