Merge accounts?

Is there any possibilities to merge my old account to the new one i use now ??? i can send the old one to you guys, i played with my brother along while ago. (i think i had VIP aswell)

No sorry we can’t merge accounts. However, if we can verify that you’re the original owner of a claim or container protection, we can transfer it to you (on request).

How am i able to do that ? i merged my old mojang account to the new java account and than i changed the name of my account.
I can try to find some proof that it is my account but it will probably be hard, because it is years since i’ve played minecraft and Tallcraft.
I remembered we built a tall eifeltower an oilrig and some other buildings.

Migrating accounts (to Mojang or from Mojang to Microsoft) shouldn’t have any impact on your data on the server. Since it’s still the same Minecraft account. Did you migrate your existing account, or do you have a new additional account (practically that means you bought the game again)?