Was umbrella merge conflict cod gold?

I hope you can help me?

My friend has registered with the pc at Blizzard and wanted to link the accounts from the ps4 when he did that the account was my game account and the psn his ps4 game account wiso we don't know, maybe you know why?

And now the big problem is that when I start my Cod Cold it always comes I have to log in with the activision account and whoever I do that always comes umbrella merge conflict, we have tried so much the internet is good and we have too the email address already changed unfortunately without success i hope you can help us?

Account settings

What do you mean by account settings?