Linked account

When I was younger, I accidentally linked my PlayStation account to my grandma’s and now that I’m older I need to play a game that I spent hundreds of dollars on, but I can’t because the link thing won’t work because I linked it when I was younger and I want to be able to link it. I’ve tried deleting the linked account that didn’t work. It still says we’ve seen that. It’s a link and it’s gonna be there forever. That doesn’t make sense. You also change that.