Data deducted without cause

Feeling completely cheated by Vodacom after noticing how fast my data is disappearing. After checking my data yesterday and over 100MB was utilised in just over an hour?! I checked my usage again this morning and 423.56 MB has been utilised in ONE DAY?! This is ridiculous as most of the usage of my smartphone is for Whatsapp and a very small amount of data is utilised for this. I am OUTRAGED! Because of fears of data being taken from my account by Vodacom for no reason, I enabled itemised billing on my account (a further charge for my account of R20 just because I do not trust Vodacom is acting legally). I accessed only Facebook for small amounts of time yesterday and did NO downloads of any kind. This is absolutely absurd. My usage has not changed since I took this contract out but my bill has increased dramatically. I have not even done one update which would cause further data decrease and have not accessed the internet. I feel cheated and want to end this contract. I will refer this matter to the Ombudsman for further investigation is Vodacom does not solve this matter.