I have 1 Service with 4 sub-services in it and all of there sub-services have more 7 sub-services in each. I tried to get data through RESTful API
/sitecore/api/ssc//item/{405D22C7-3BB0-4F95-9A82-CD32E2544ED5}/children?language=en&fields=ItemName
But this API is giving me only data 4 sub-services and not reach next level. API is not giving me data on 3rd level sub-services(7 sub-services).
I believe that the Item Service is simply returning the immediate child items rather than all descendants of the item.
The PDF Developer's Guide to | 1.1 What is Sitecore.Services.Client? contains a section 3.4.3 on how to 'Retrieve an Item by Content Path' which does not suggest that all descendants would be returned by the /children route.
Depending on the version of Sitecore that you are running, the sitecore/api/ssc/aggregate/content/Items('/sitecore/content')/Children route in the OData Item Service can be used to Retrieve all children of an Item. Alternatively in earlier versions of SSC you may have to script recursive calls to the Item Service to return all descendant Items below an Item.