Galaxy S8+

I bought a Galaxy S8+ & now it's saying that moisture has been detected & shows icon. I'm unable to charge phone. Took it to Samsung V & A Waterfront while on holiday couple of days ago. Guy said icon will go away. I'm now home in EL & moisture icon still there. Samsung claims phone is IP68 rated. TV adverts even show phone in swimming pool. Now I'm stuck with R15000 phone I can't use. Store says warrantee doesn't apply to water damage. I'm not impressed nor happy