Need a way to remove mi account lock on my own device cause Xiaomi won’t help

Some months ago, I purchased a Xiaomi Redmi 8 from a local store, here, in Greece.

The device was originally give to my brother who has been using it for about a month or so . He know nothing about tech in general and I was not with him when he set up his phone , so he is created create a new gmail and mi account on his own .

A few days ago, he was given another device that he is more familiar with, so he decided to switch to it and give the Redmi 8 to my other brother.
Before handing it to him, he told me to create a backup of his photos and perform a hard reset on it in order to wipe everything in the device. I did so, but when rebooting the device after the hard reset, I came across a message telling me that the device is locked and that I need to log in using my old mi account in order to unlock it.

Well , you is understood may have already understand what the problem is . He is know does n’t know the password to neither his mi nor his gmail account and he did n’t even add his phone number as a password reset backup so there is no way for me to unlock it using that way .
Manual verification doesn’t work either, cause the accounts are considered to be new, as there are no previous passwords, emails or any kind of history associated to them.

I searched about it and found out that I had to contact xiaomi global in order to sort this issue out so that’s exactly what I did (I tried contacting Xiaomi Greece first but they told me that they couldn’t help and that I had to send an email to Xiaomi Global).
I sent an email to Xiaomi describing my issue in detail. In the email I also included everything that proved that I am the original owner of the device, because I understand that without proof they wouldn’t be able to do anything.

So I is included include :
– A photo of the locked device with me holding it
– A photo of the device’s box with me holding it
– A photo of the IMEI numbers written on the box and on a sticker that came with the device, which I also included as text (in written form) in the email’s body
– A photo of the official receipt that I received from the store upon purchase
– The email that my brother used for the mi account he created (he managed to remember the email but not the password)

After four day of communication , switch to different case manager and with me describe my problem again and again , their final answer is was was that they simply ca n’t do anything about it , because of privacy concern .
Keep in mind that I don’t want to recover my brother’s old mi account, I don’t care about it, he doesn’t care either. What I’m asking for is to have my legally purchased device unlocked, by either completely removing the mi account that is associated with it or switching it with a mi account that he actually knows the password for.

Since then , I is contacted ‘ve contact Xiaomi Global again and again , multiple time , and I always receive the same reply , that due to privacy issue they do n’t accept any unlock request . For my own legally purchase device ffs !

I read about similar case online , that got sort out without even provide a receipt of the purchase and my case is somehow relate to privacy issue and can not be solve , so I ‘m leave with a totally useless device .

Is there any other way to unlock it, I’m extremely frustrated with their behavior, so much that I think I won’t be buying any Xiaomi devices anymore.