I know this is a ridiculous procedure, but ... if you go to www.refunds.aa.com, you should be able to view and print a receipt for any charge related to an unflown itinerary. If you have the ticket number for each charge, you can just plug it in, otherwise you can search for it.
Don't even get me started on all the details of why I know this, but it relates to an e-ticket that I never received, and was "overwritten" by a later payment related to the same itinerary. AArrgh!