It is rather typical that you have to send in the actual BP's along with an eticket receipt if the miles do not post. This is not atypical for any airline. As already suggested just make sure that you make photocopies of the docs sent in and rather mail the whole thing with tracking/certified to ensure actual delivery.

I had four flights on UA that didn't post automatically, although three of the BP's correctly had my BD FF printer. It took about month and a half after I had sent them in to post on my BD account.