Experia z2 not so waterproof

My brother took a experia z2 out on contract from mtn in July 2014. In September he tried out the waterproof capabilities that you FALSELY ADVERTISE. He did this WITH holding the ports closed just incase,within the specs you claim the phone would still operate. After the second photo the phone started malfunctioning. Multiple screens started opening. He then took the phone in to mtn and it was apparently sent to SSS as where the multiple complaints iv read above. Clearly not an isolated problem. In October he went in to pick the phone up and was given the unrepaired phone back by mtn sayin the warranty is void due to water damage. Because the testing is done by SSS they are unable to assist.The phone now after coming back is not even able to switch on.Pressure testing messed it up even more. He is paying R469 for a phone that doesnt work.Definitely advising him on a Samsung S5 sport on upgrade.He has now sent me the phone here in Jhb to get some sort of assistance. Sony cant possibly be this oblivious to faults on the phone they CLEARLY advertise as being able to take photos under water if they receive this many complaints and still do nothing in this regard. Please assist!!