Hi there, I need help with removing the activation on iphone 6s.

My auntie gave me her old iphone but she lost the purchase receipt and forgot the icloud that was set in this account but we have the physical box here. my auntie works in japan for many years and she bought iphone6 during her days there but unfortunately, time has passed and she bought a new phone and abandoned this phone for years. last week she found this phone and decided to give it to me. she shipped this phone from japan to the philippines and recieved it yesterday. but after that i opened it and it showed me an activation lock confirmation. my auntie suggested me to take it to the repairshop but they only offer me a bypass method which i did my research that it has limitations when doing this. so i decided to do it the right way. now i tried the activation lock support thingy on apple support but for some reason i can't recieve the confirmation link in the gmail i provided. what should i do with this phone? im kinda bit losing hope to use this. its such a waste if i just throw this away.