[mothered]

So I’m doing DNA with my roommate’s account with the same address but different name and card to my account which I’ve done an EB just 2 days ago (successfully ofc). The rep straight up told me that they can’t process the refund on my friend’s account as the button for refund is grey out.

You're performing the DNA "as your friend", so I don't see why the refund cannot be processed.

In terms of a "buyer's account", your friend Is allowed to legitimately use the same residential address under his/her name and payment system. Though, the email address must be separate to yours. "Seller accounts" are different- one account per household and you'd need prior approval from Amazon for further accounts.

They insist on opening an investigation but I narrowly avoided it by making excuses and such.

What exactly did you say?