RDS Custom for SQL Server the status is blocked on DELETING for more than 24 hours

Hello, I did some tests about the creation of RDS Custom for SQL Server with several configuration. And after, I delete all the DB instance but only one instance stays at the status DELETING. I can't delete it with the aws cli because I've this message : An error occurred (InvalidDBInstanceState) when calling the DeleteDBInstance operation: Instance database is already being deleted. How can I force the delete of this DB, because even if the status is DELETING, the bill continue to increase because of the RDS custom, hour after hour. Thank you very much.