I also received notifications from my old account on my real gmail, but just couldn't log in anymore.

alexsmolik, on every war there are victims. If there was any chance to fix this situation, they would do this. But  they've made the decision, after all you and me are just insignificant users comparing with numbers of youtube users. The check was paid and the owner has the right to decide. They won't roll back. Maybe you are a partner for them, but your numbers are huge.

After all, you had you account for free and bla-bla-bla. They don't owe you anything. The only thing you can get here is excusable warmness of the support lady.  

You can register new mail and resend mail to your old mailbox. You have to accept that. I did that.