Vodacom .... Seriously

This is the second time within such a short period of time that I am contacting them regarding 2 different numbers! My data on my IPhone 4 today was depleted within 1 hour of purchasing the 100mb data bundle. My 1st 100mb data bundle lasted me from the 1st of Feb to the 15th! Please explain to me how this was used so quickly when during that time I sent 1 WhatsApp,had all of my apps closed and left the phone on a counter. I then spent over an hour on the phone to Vodacom. The conversation ended with me in tears and my dad trying to sort the problem out. I gave them permission to look into my data usage for that hour... what more could they really want from me!!! I'm finished! Vodacom only seem to respond when you complain about them on a consumer forum so here goes!!!<br>