Unexplained data usage & no response from Vodacom

In June I upgraded my cell phone and internet contracts at Vodacom. On 7 July I received an internet bill on which I was charged double for my monthly fee and all my data had run out by 14 July. That is 4gig data (3gig internet contract, 1gig cell phone contract) in 2 weeks! I made a call to Vodacom customer care and went in to a Vodacom branch (Preller, Bloemfontein) to find out what the problem was. They lodged a complaint for me and would call me \within 3 or 4 days"with an answer. I also sent an email to Vodacom a week later. I have never exceeded my 3gig limit on my internet contract. I was told that reaching my limit was because my laptop and new Samsung Galaxy S6 had been updating apps. Can updating apps and using Whatsapp and Facebook use 4gig in 2 weeks? I then switched off all updates on both devices. Nevertheless"