do i prove it in a way send some eth using that erc20 address not something reasonable?
Dude don't worry, just do it. Create your new wallet (ethereum address) and send something from old wallet to new wallet and show proof of tx hash here. I think it will prove that you are still the same owner and I thought it would be a reasonable proof for everyone.
Don't worry, no one can tag you if you are completely innocent. So after you managed to prove it then your problem I think is solved.