Hi @Dušan Hudeček ,
Since you are locked out of the tenant and are the only global admin on the tenant, the only way to regain access is to contact the Azure Data Protection team or create a support request. The number for the Azure Data Protection team is: 866-807-5850
If you had access you could follow the steps to transfer the subscription, but that will not work if your account is blocked.
If you would like to create a support request, I will leave information in a private comment for enabling one.
-
If the information provided was helpful to you, please remember to "mark as answer" so that others in the community with similar questions can more easily find a solution.