Please help me. I cannot redeem my Battlefield 2 copy in EA app.

Hi there! I have purchased a few months ago a new (sealed) copy of Battlefield 2 Complete Collection and I want to add it to my EA account but it doesn't work.

Can someone please advise me on how I can redeem the code? It's my favorite Battlefield title and I would love to have it in my EA library.
I can provide proof of purchase in case that is necessary. Thank you!