Send more combined bills dating as far back as a few years ago, combined account info, leases (if you have them), more heath insurance documents with both your names on it, etc. The further you go back with dates the better. Even more photos, emails, cards and letters from family and friends to both of you, etc. Bombard the hell out of them with info! Based on your list I think it's ridiculous that they are asking for more. Sounds like the person who reviewed your file was in a bad mood!
Are you guys common-law or married? If you are common-law they may want more proof indicating that you have been living with each other for more than one year. So if you can get a pile of bills and other important documents that have dates going back for the past few years or so, then that should be good enough.
Sorry to hear about this. But I'm sure with more proof all will be fine.