Vodacom Charging for Warranty Service

I sent my iPhone 4S to Vodacom Madeira to be repaired under warranty. The iPhone is a contract phone which i took with Vodacom last year (2015). I was told that the iPhone has been written off as it was picked up as water damaged. I understand that the warranty doesn't cover physical damage or water damage and for this reason i accept if they say they cannot repair due to water damage, meaning they reject the warranty repair. However Vodacom made me pay for the assessment of the iPhone.<br> Rejecting the warranty repair should be enough but don't charge me for something that falls within the scope of warranty. The assessment of the device is scope of warranty, Vodacom stop ripping us for nothing.