Billed me 1GB while in a bad reception area!!!!!!

Every month for the past year and a half. I receive a 1,2GB bundle which would last me at least till the end of the month. While on Holiday in Northern Natal between, the 1st-3rd January 2015, I had bad reception (network indicated NO SERVICE most of the time) and my phone was off for at least 2 days. While heading home on the 3rd I received an Sms indicating you have 700MB data remaining. On a normal, very busy month, I would only receive this sms around the 20/27th of the Month. I phoned Vodacom immediately indicating that I had only been onto Whats app once and Instagram once and it was impossible that I had used up the indicated amount (My celluar data usage on my phone indicated 17 MB used in Whats app/Instagram while my Current period indicated 738MB) All of my celluar usage apps had been turned off on my Iphone and I had done no upgrades on any apps. This is after learnt my lesson with a shocking data bill in the first 3 months of my contract. Customer Care promised too phone back!! Which never happened, and they refused too help me after I phoned for the second time yesterday. I will not stay with a Company that does not take care of it's Customers.