How to get correct data from API?

Question

Android

There is some API for making calls.
It has a GET request to add a call
https://callbine.ru/api/v1/call/add/?phone=NUMBER_T...
It returns the id of the call, by which you can find out its status
https://callbine. ru/api/v1/call/status/?call_id=ID...
Always ends up with the same status (dialback), although the API is working, it is already being used in another application.
There is also a second request in the documentation to get the status (POSTBACK), but I can't apply it in an android application (perhaps I don't understand)
https://yourdomen.ru/?phone=[phone]&id=[call_id]&u... ]
What could be the problem or how to use a POSTBACK request to get data?