Hello Monsuru Adedokun
Thank you for contacting the Microsoft community Q&A support.
Since this account is the only Global Administrator in the tenant, you need to contact the Data Protection team for assistance.
You can either contact using the phone support option or create a ticket with another account.
Kindly follow the link below to get more information on how to go about this.
Let me know if further assistance is needed.
Babafemi