Incorrect Billing

I have been a member of the vodacom community for a number of years now. Over the past 3 years they have either billed me incorrectly or have removed data off my device for no reason. My recent encounter with them is regarding the billing of the data on my Ipad. First of all I asked them not to renew my contract and to continue just with the data, however, they still have me on a contract which will pose a problem when i leave he country in April next year (this was what i was trying to avoid), secondly, i changed my banking details in the December 2016 of which vodacom was notified. Vodacom have been billing me from my new banking details since January 2017. They some how decided to bill me at the end of September from my OLD banking details (obviously no money was there and i found it strange that they never debited me the month before, or i assumed i missed it), this is after 10 months of debiting from my NEW banking details. They (Vodacom) double debited me at the end of October and penalised me with R100 for the debit not going through the month before, for a mistake that they you made Vodacom! i phoned Vodacom on the 25th of October (the day of the debit) to confront them regarding this. I must have spoken to 3 consultants, one who seemed very unhelpful and i raised my voice to her because of her inability to assist and due to my obvious frustration(Thebogo). I was finally helped by a young lady by the name of Gugu who explained to me that vodacom was at fault and that i have had a clean credit history, she said she will log the incident and vodacom will refund me in 3 to 5 working days and i was also promised an sms of a reference number (i even confirmed my cellphone number with her). I never received an sms with a reference number and its been 8 working days and i haven't received my refund back. R100 is still R100 to feed my children and family. My husband is working in the Uk and i am sole provider here for my son and i have another baby on the way. The number in question is ********** 418 which is the number of the sim that is in my Ipad of which i receive 2GB data each month of which i pay R109.00 p/m (i was only suppose to be paying R99 p/m because it was not supposed to be a contract). Vodacom debited R318.00 at the end of October. I dont see the need in calling through as i feel i get absolutely no assistance. Once again, please assist here Vodacom and i hope and pray i get no trouble from you for the remainder of my time here in SA.