You can check Postback events data for your campaigns by selecting Acquisition Campaigns from Reports tab.
Postback events data are also available for your offers by selecting Offer Performance from Reports Tab.

Click on Metrics button  and select Postconversion Event

Then click on Dimensions, select Offer and click on Run report button

In the report you will get, you will see the Postconversion events data in the last columns

click on  to break down the report by Offer data in order to get the reference of the events name

move the mouse cursor over the data in the Event column to see the related event name