Contact Google Play services. They helped me out as well when my savegame crashed on a vault where I had bought a Mr Handy on. They refunded me the full 1.09 euro.
Fill out the forms, be specific and add the receipt you got in the mail. Maybe even the savegame to probe you didn't receive all 6. Also you may want to wait a couple minutes/hours. I thought I had bought a mr handy on my 2nd vault, and the transaction was canceled, so I did it again... long story short now I have 2