Hey broski I am facing the same issue. I bought the Advance Pack for 3 different accounts and nothing showed up for a week now. Contacting support will redirect you to Steam Support, Steam Support can't help with DLC so they will direct you back to EA, , they'll give you an AI-generated response then slowly putting you into a reply loop with countless back and forth before IP lock.
Steam can try to look into why you got charged twice for the product but further than that is out of my knowledge. Good luck to you man.