Data simply disappearing

There is no way that data can be used up as quick as mine. I have loaded new data bundles of about 3GB in the last week...Not watching any videos or anything special. Simply using my phone as a hotspot to read emails etc?<br> <br> I need an explanation as to where my data is disappearing to?<br> <br> I just loaded another 250MB, sent 4 mails and my data was back at 0mb??<br> <br> This is not possible?