Theft of airtime minutes and data

I migrated two years ago from MTN for signal only, and the first two years went well, except for *****ing data from me in August this year. No feedback from Vodacom despite me tweeting the problem. Today I could not make calls and when calling 111 I was told my upgrade kicked in today and not 1 November (tomorrow) as originally told. They told me I used up the entire 50 minutes allocated for November in one day, yet I added up the entire 4 calls I made of less than 1 minute each call, and if my math is correct, it adds up to 4 minutes, not sure how Vodacom works that they can take my entire 50 minutes for 4 calls made of less than a minute each. If I do not get a response regarding this theft, I will take my phone back and cancel the contract and rather go back to MTN, as they have since installed a booster in our house to improve the signal as my husband stayed with them. Absolutely pathetic!!!