iPhone issue

I bought my 15 plus at istore Eastrand mall cash I was given a slip to insure my phone which I did online and I waited for their respond to say it's insured I did not it was 2023 December my phone fell inside the water now it's not working I can't claim my insurance because they never got back to me I took it to istore they were unable to help me the phone I thought it was water resistant so I don't know what to do anymore when Istore does not help me I only used this phone for a month .