Without having my instance in front of me to have a play it is a bit tricky but looking at it the quickest option would be to just return something like
{"Receipts": paymentsInfo }
Although it would need some testing, as an ugly workaround it might get you going.
Ah yeah that will get you. So you would need to do it as an array and tweak it in your next node or in your next node use the expression editor to add in the Receipts part.