Hi, so I was one of those who bought an amazon warehouse mini 3 pro that the original owner purchased bound to his account and then returned for a full refund.
Now I purchased this from amazon and going through the process of trying to registed it under my account.. which I find a bit problematic.
Amazon told me they are not able to contact the owner and upon my suggestion that they should verify the product has been properly deregistered before issuing a refund they replied that they do suggest to de-register and reset it, but apparently they do not verify this, yet still resell these returned products.

So after contacting DJI I've been told that it is not possible to de-register already bound product without the original owner agreement. There really is an issue here.. now, amazon is to blame here for not verifing the original owner properly deleted his drone from his account upon return, but there really should be a solution offered by DJI if somebody will get stuck in situation like this. Imagine the original owner no longer have access to the email address and would like to move his drones to a new account. DJI should be able to accomodate this reasonable request from the owner. Maybe request the invoices of purchase, pictures or live video chat with all the serial numbers of the drone/box etc.. then send an email to the original email address to notify them that there is a request to deregister the drone and give them some time to respond to that, if no response.. maybe send another reminder and if still no reply go ahead and de-register the drone. If there is a response that blocks the process, maybe ask them to provide proof of purchase/pictures/video chat with serial numbers etc.. but there really should be a solution to unbind the drone from account. If only for the 'no longer got access to email' purpose. There really should be no dead end like it is now. I can still return the drone if they won't be able to get a reply from the owner, just thought to share this here as it is pretty standard procedure to recover an account if you lost access. Even apple will delete icloud account from locked phone if you prove you are the owner with invoices/serial number etc.

Couldn't agree with you more on this issue.  

Hope you can understand that we cannot perform binding, and therefore, we cannot change the binding or unbind a product. In order to protect our customers' legal rights and data privacy security, it is needed to perform unbinding via the associate account. Therefore, we recommend that you contact the original owner or seller for assistance in unbundling. If you can't contact the original owner, you can contact our support team for further help. And we noticed that our support team is already following up on your case. Hope you can wait for the update patiently. Regarding your feedback and suggestion, we will also forward them to the relevant team.