Data bundles

Hi, I bought 2x 1Gig on the double data app 6 days ago and to my surprise when I got an sms that my bundles are about to be depleted. There is no way I have used 2Gigs and it seems the extra 1 gig was not allocated. I called customer service and they could not explain how this could be. At first she said it was only 1 Gig that I loaded, then later she said I have used the whole 2 Gigs? My thing is, if you check my data usage on apps I use, there is no way I used 2 Gigs, even the vodacom app, shows the remaining balance is from 1 Gig loaded, meaning the double data promo was not allocated!