Ok - so what you need to do is get the list id for the list items (i.e. the repeating data) back in your repeating data somehow. Then in your CAML, you have to include the ID field in order to update.
This post has a little bit of info on including the ID: https://www.infopathdev.com/forums/p/19259/103343.aspx
I'd probably do something like have another field in my repeating section for some kind of unique id - concat the result of the now() function with the parent id and the awardee account name or something. And add a field to store the list item ID. Then add a data connection to the list you are submitting data to - don't bother querying on load. Make sure to include the list item ID field as well as your new "unique id" field. In your submit rules on the submit trigger in your repeating data, after the submit, set the query field in your new list data connection to the unique ID and run the query. That should get you back the list item ID and then you can set the ID field in the repeating data to the correct list item ID. And, of course, adjust your submit rules and your CAML so you are including that....Then the update list items method knows what to update! :)