Disappearance of mobile data even though mobile limit settings are in place

<p>I purchased 500MB of data on 03 January. I am a regular user of setting up my mobile data limits as soon as I top up and most of the time my data usage is spot on compared to a balance enquiry using *111# option.</p> <p> </p> <p>This morning I was on the internet and a screen popped up to say data bundle has been depleted. Upon checking my data usage setting, I only used 137MB to date. I checked my applications listed, in the data usage setting, and the restricted background data setting is ticked for all my applications.</p> <p> </p> <p>Upon contacting Vodacom, the consultant can only iterate my balance enquiry, that I could have received via the automated service, however I would like to know what was data was used on. I have heard of this happening to other Vodacom customers and it just seems unfair that I am now at a financial disadvantage having to purchase data again.</p> <p> </p> <p>Kindly advise.</p>