Huge Data Usage and NO Answer

<p>So we have 2 company phones that data just spiked over the last few days, we ask Vodacom and they say " we will have to investigate and get back to you" but in the meantime you have to pay for that account - how is this possible if you can't prove what it was used on ? Also the best part is that both these numbers are 90% of the day on the wifi ! Please explain Vodacom</p>