Does your interface/package/scenario fail or succeed?
If failing: in which step is it failing and which error message is shown?
If succeeding: check in which step of the flow that your object is not inserting the records like you want. You can perform all the SQL's manually one by one on the back-end systems to verify where the problem is occurring.
As you said you see the data in C$ but not in I$ or Target . am i right ?
First check if the data you are trying to load is not already present in the target . As you have mentioned you are using Oracle Incremental Update and it check with the target for insert/update records , if records already present they wont be loaded into I$ or Target .
If that is not the case make sure your commit is true.