Data disappeared

Last night I received an SMS telling me I had 1gig of data left<br> This morning it was all gone!<br> I have a secure WPA connection password protected. <br> That after only sending a few emails and a bit of social media. <br> I have just spent the last 30 minutes on 155 with your consultant and was kept on hold for ages with no solution. The call eventually dropped still with no solution. <br> Where is my data?<br> I would like this escalated please. It's impossible to use 1 GIG of data in such a short time. I wasn't downloading a movie or anything like that. <br> Poorly trained staff at call centre doesn't help