BP Cashback gone from statement

I have created this blog to see whether other people have had the same experience with the BP Citibank card in Australia. I have had this card for over 11 months and took advantage of the cash back offer. All was going well until last two statements I found out that I didnt get the 5% cashback from my BP expenditures. The 1% off everything I was still getting but the 5% didn't appear on my statement.

I called up and they said that it will appear in the next statement. Nothing. Called up again and they said someone will get back to me within a week's time. Nothing. Called up again and talked to the manager. Have you had this experience?