A Microsoft file hosting and synchronization service.
Hi Ko Wai Mei,
Microsoft 365 subscriptions progress through several lifecycle stages after expiration. For most subscriptions, this includes an Expired period followed by a 90-day Disabled period. During the Disabled period, users cannot access Microsoft 365 services, although the organization’s IT administrator may still be able to access and back up the data.
Please contact your school's IT administrator to confirm the status of your alumni account and determine whether any data remains available under the institution’s retention or backup policies.
If the account and its data have already passed the applicable retention period and reached the Deleted stage, the data is permanently deleted and cannot be recovered. Assigning a new license or adding a new subscription will not restore data associated with the deleted subscription.
For more information, please review What happens to my data and access when my Microsoft 365 for business subscription ends?.
In case you do not know who is your IT admin, kindly refer to this article: How do I find my Microsoft 365 admin? - Microsoft Support
I hope your issue gets resolved soon. Any updates would be greatly appreciated.