Vox Telecom data charges are plain wrong!

I was amazed to be notified by VOX that on the 4th Feb, I had used 60 623.16 MB of data and it was explained as due to email downloads. Assuming a generous email size of 1 MB per email, then according to VOX Telecom, I had received over 60 000 emails between 11am and 5pm on that day! Impossible!!! My inbox shows my usual daily receipt of 20 to 30 emails. Vox refuses to accept that they erred, and pass a credit, so I challenge them to search my PC for those allegedly downloaded emails..