Unusually high usage on cellular phone

I need some assistance and or guidance in how to handle my complaint against Vodacom?<br> I revived a sms from Vodacom on Saturday morning regarding the unusual high usage that had been detected on my cellular phone to the amount of R 12 024.55.<br> <br> I had this contract for many years and this is the first time that I experienced this kind of a problem. Is it because I upgraded my contract or is it because of the Huawei P8 smart phone that I am using? <br> How can Vodacom expect me to pay this amount?<br> <br> I asked for Vodacom to investigate and provide me with details on this high usage and why it took them so long before notifying me about the high usage.<br> <br> I feel that Vodacom is not looking after their customers, and if only their to see how much money they can get o