Hi @Mohammad Hamza
Thank you for reaching out to Microsoft Q&A.
I understand that you want to recover global admin access to your subscription, you can create a new Azure tenant and raise a support ticket from there.
To create a new tenant, open in-private/incognito browser window and access https://azure.microsoft.com/en-us/free/ to create a free Azure account.
When you create a new tenant, you by default become the Global Administrator of the new tenant and have full access to all the options in that tenant.
Once the new tenant is created, you can submit a support ticket through: https://go.microsoft.com/fwlink/p/?linkid=2024339
When creating the ticket, provide the new tenant ID and explain to the Microsoft support team that your company lost access to the Azure Subscription Owner and Global Admin due to the previous admin leaving. Mention that no one else has Global Admin access and request their assistance in restoring Global Admin rights for your subscription.
Let me know if you have any further questions.
Best Regards,
Harshitha Eligeti.