PRIOR_AUTH_CAPTURE not working properly

I have setup auth only mode for transaction.. When customer do order, I am getting this message in order note:

This transaction has been approved. on xx-Jan-xxxx xx:xx:xx UTC with Transaction ID = xxxxxxxxxx using AUTH_ONLY and authorization code xxxxxx
Here: I am getting all value when order received. and working perfect.

Case 1:
Now, When i do order status completed then It was not auto captured. I was looking auto-capture once order completed.

Case 2: I click on capture button on admin order details page manually. Then i get this message:

This transaction has already been captured. on xx-xx-xxxx xx:xx:xx UTCwith Transaction ID = 0 using PRIOR_AUTH_CAPTURE and authorization code
It is sending 0 value. instead of actual transaction id.

Support told me: the sale was authorized and recorded but our step to capture is not transmitting to Authorize. Customer service mentioned something about a ‘response code’ on Woo to confirm order was completed.

Expecting:
1. Can you fix Prior_Auth_capture issue?
2. Can we combine with completed status if possible?
3. If we need to partially accept payment then how can we do from this plugin?
Means if order $100 and we need to charge $50 for now. Remaining after sometime etc.