No help from Vodacom!

My cell phone data is being eaten up/******/disappears when I AM NOT USING MY PHONE. I hardly do. This has been happening since April and I have reported it twice. Before then, my average cell phone bill was around R300. Since then it comes to well over a R1000 every month and nothing has changed on my side. Cresta said they \could"not help me. I keep on getting messages from Vodacom to say I am \""out of bundle\"" (which never happened before). On Thursday last week I received another such message"