Q: Activate iPhone 5s

I have an old iPhone 5s .. actually I have 2 of them .. one was mine one was my wife's.  We've replaced these with iPhone 6's and would like to give our old phones to our grand children.  I have the apple id I think I used to setup the phones but that was years sgo, I have a password that I can use to login to my apple account and my icloud account but this account/password will not let me activate the phone .. the error message says incorrect apple id "xxxx@aol.com" cannot be used to unlock this iphone but on the login screen it suggests that the correct apple id is x...@aol.com so I'm pretty sure I'm using the correct apple id .. I've also seen suggestions that the icloud find my phone feature has this device listed but I can't see it when I log in and look ..

Any ideas?  I think I've gone through all the correct steps to get this phone unlocked but it's not playing ball.

TIA,

Bob