Data disappears without being used!

Yesterday we topped up 1Gb of data on a MBB device. During the course of the day we sent a total of 20emails (max 200kb word documents) and viewed roughly 20webpages. Somehow the gig had been used up! IMPOSSIBLE!! I have worked in a mobile call center in SA and I know how easy it is to lie to a customer to get them off the line. Today I called back as this had happened again! 1Gb was put on at 8am, we never connected a single device as we were using work wifi, then (whilst driving in the car with the ****le off!!) the data ran out?? we NEVER connected or viewed A SINGLE WEBPAGE yet it is gone! I Called the call center and refused a 48hour callback (this is not a legal norm, this is simply a line used by agents in all centers!) and demanded a manager immediately. I was put though to a \manager"who clearly was another agent pretending he was a manager as he couldn't even authorise any corrections. After he tried to lie his way out of it i mentioned the CPA and my experience in the same position he is in and suddenly he was helpful and has promised a callback before the end of the day. This is still being waited for"