Sony India — fault design waterproof design /water resist design ip65 ip68

Address:	Jodhpur, Rajasthan, 342011
Website:	www.sonymobile.com/in/products/phones/?utm_source=Sony+India&utm_medium=Banner&utm_campaign=

My sony xperia z3+ which is desing to take photo underwater (As claimed by company) is been dead and not working when i take it underwater for just 30-50 seconds its has ip65 and ip68 waterproof/waterresist mark now company's authorised service center said to pay rs 4-5k (4-5 thousand ruppes) as a repair cost. Why would i pay to service center when its company's desing fault