First check whether another seated owner can manage the team. Do not share the missing owner's sign-in method or recreate their account to impersonate them. Membership changes must use an authorized account.
If your organization no longer has access to its owner, contact support with the team name, your account email, and an explanation of the ownership problem. Keep credentials out of the message. Support must review the situation before any access correction; a company name or support code alone is not proof of ownership, and a request does not guarantee a transfer.