Unable to access account

Hello, so I have encountered the problem of migrating my previous account (the current one linked to this one). This really upsets me ofcourse. I have spent many hours and and even bought a rank on my account, but due to the migration of Microsoft, I am unable to recover the account. Many will ofcourse say it is my own fault, but I simply never knew that the migration existesd, because of not opening the game for years.
Would it be possible to transfer my content to a new existing account, including my rank?

 

Sadly you cant transfer your content to a new account
But if you email [email protected] you can transfer your rank if you have proof of purchase!

 

I have checked everywhere, including different Emails, bank accounts etc. The history simply is not accessible that far back in time. I am understanding that you need some sort of confirmation regarding the purchase, but I simply don't understand is why you need a "receipt" if you will from 5 years ago, when the receipt clearly is not saved. Not that the issue is big, I would just love to spend some time on a server where i spent a lot of my childhood.
Thanks again.
If an staff member would be able to help, it would be delightful.