There are two possible reasons:
The deleted files are in the recycle bin.
When deleting a project, check if the recycle bin is enabled. If it is, deleted files will go to the recycle bin, and there are no fees for using the recycle bin itself. However, data in the recycle bin will still incur storage fees based on its original storage class.
The bill is for the day you deleted your projects and logstores.
After you delete your projects and logstores, you will still be charged for that day and receive the bill the next day. Check if the bill is for the day you deleted your projects and logstores. For more information, see Query bills.
Fees are deducted daily from your Alibaba Cloud account balance. A bill is generated every day based on the resources you used the previous day.