Hello Naqib Asri,
Thank you for posting your query in the Microsoft Q&A Community.
You can see this organization as one of the organizations your account is attached to because your account has been invited to the Tenant in the past.
Since you have access to the tenant's user blade, it's worth checking your user account there. Check when it was invited. You can also check the audit or sign-in log to see if activities are related to your user account.
If you still don't recognize any user in there or are sure you weren't invited to the tenant by request, Kindly leave the Organization using the Leave an Organization feature in Azure.
Follow the link below to see the steps involved in leaving an Organization
https://learn.microsoft.com/en-us/entra/external-id/leave-the-organization
Let me know if further assistance is needed.
Babafemi