A cloud-based service included in Microsoft 365, delivering scalable messaging and collaboration features with simplified management and automatic updates.
From your description, I understand that you are facing an issue with domain ownership. As the domain ABCD.com is already associated with another M365 organisation and you cannot access the previous admin account.
Given this situation, the best course of action is to contact Microsoft support, who can assist you in verifying the ownership of the domain and help remove it from the old organisation. When contacting support, please be prepared to provide proof of ownership for the domain. This may include domain registration details, invoices, or any other documents that prove you own ABCD.com.
More information can be found Find Microsoft 365 for business support phone numbers by country or region - Microsoft 365 admin | Microsoft Learn
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