Hello @Ananay Ojha
I see you have been facing issue with deleting a vault from azure backup service. If it complaints about the storage account still being associated with the vault, you need unregister the storage accounts from the vault->backup infrastructure blade->Azure Storage accounts -> Unregister storage account.
You can see the steps on this document https://learn.microsoft.com/en-us/azure/backup/manage-afs-backup#unregister-a-storage-account
Post unregistering the storage account from vault, you should be able to delete the vault.
Let me know once you perform these steps.
(If the response is helpful, please accept the answer for the benefit of other users in the community)