Why am I not eligible to request a refund?

Did you already try to contact the official Apple Support about that? Only they can look into your personal data and tell you about the reason.

You can use this link as a start:

Apple Subscriptions and Billing Support

Or give them a call:

Contact Apple for support and service - Apple Support

Are you part of Family sharing and you are not the organizer of the family group? This might be a reason for that.

They said they don’t have information why is it eligible for a refund