iStore deception and questionable practices

In December 2017 I got a new iPhone X on contract under a 1 year warrantee from iStore. In April of this year the facial recognition camera stopped working. I took the phone into iStore and was told it had to be replaced. They gave me what I thought was a new phone. Just over a week ago, my phone landed in the bathtub an died. This despite the Iphone X being advertised and marketed as IP67 rated. This is an international standard which means that the phone should be submersible under 1m of water for up to 30 minutes. Yet my phone died after being in less than 300mm of water for less than 5 seconds. I returned the phone to iStore who in turn told me that the warrantee is void due to liquid damage. The phone being IP67 rated should not have sustained liquid damage under these circumstances. Through this dispute with iStore it has become apparent that back in April, when my iPhone was replaced under warrantee, iStore replaced it with a second hand phone and not a new one. This would explain why the phone failed under circumstances well within its advertised capabilities. iStore South Africa trades in deception and lies with questionable practices. I love the Apple brand and have been using it for 10 years, but @istore South Africa are destroying the brands credibility and treating Apple users poorly.