I need to apply for a DLC refund.

Hey Angeliya-Choe​ , if you purchased a DLC for a game that you do not own, please contact EA Help. They should be able to assist you with that: How to get help with your EA Account. Let me know if you have any questions.

Thanks for your reply. I see.

This is a terrible shopping experience.

Hello Angeliya-Choe​,

Downloadable content (DLC) and in-game currencies are not refundable if purchased separately. I believe you are not able to refund the DLC.