how to get the hash key in billingControl?

I am trying to UPDATE the HardLimitAmount field using rest api but I always get an error: 404 Not Found.

When trying to use the GET method using the link below, I am able to get the BillingControlId,

"https://base url/fscmRestApi/resources/11.13.18.05/contracts/100014821314351/child/ContractLine/100014823126154/child/BillingControl/"

but when I am using the BillingControlId to get the specific record, I always get get an error: 404 Not Found.

Upon going through oracle documentation, there is i think a hash key that is needed to be able to UPDATE a billing control.

BillingControlUniqID(required): stringThe value of this parameter could be a hash of the key that is used to uniquely identify the resource item. The client should not generate the hash key value. Instead, the client should query on the collection resource with a filter to navigate to a specific resource item. For example: products?q=InventoryItemId=