Poor response

I have a Thank You card that I use to get points so I can get discounts when I buy at Edcon stores. I use the card mostly at Engen garage since I fill up my tank every week. I even registered on the Thank you website so I can track my points every 2nd day after pouring petrol. On the 2nd May I checked my points and they were 61 040, I then filled up on the 7th May and logged in again only to see my points were now 21 305 and yet I've never used this card for any purchases. I then sent an e-mail to enquire on the same day and was told that the case has been forwarded to the Loyalty Rewards Management Team for investigation. It's now the 15th May and have still not heard from Edcon. And since I filled up on the uth my points are now 28 649. What I would like to know is what happened to my points?