Overcharged account

I have a wifi contract with vodacom wher i have been receivinga 2 GB pm for over 3 years for R129. A few months ago I have upgraded to 5GB pay in R168 pm.. To my surprise on thursday the 26th of April I see a debit order of R1563. 78 from my bank account. I then contact vodacom and they tell me that I have called them on the 26th of March requesting for an open line for data. I dispute this because I obviously have not done so. They later send me an email sayin it is an email of goodwill gesture which decreases this R1563. 78 to R384. 16 as I have been downloading content for my IPhone device. Angered, I respond to this email asking what is this gesture and why do I suddenly have an Iphone contract with them that I am not aware of. I also call again to query this email.. On the second call I am told that since I have been a good payer vodacom has upgraded me to an open line. I ask why so without my permission and they tell me that is why they have sent me the email of goodwil gesture. At this point I am very upset because in my first call I was told that I had called and changed to open line. I tell the consultant ent that I cannot be **** to and told that I have called to change my contract, later on be told that vdcm has without my permission sion changed my option. And worst of all they talk about ut a device that I do not even own. Since this consultation has ended in vain. I decide to call my bank and reverse this rediculous amount. It is reversed on the 26th... And debited again on the 27th with the same amount of R1563. 78 I am very angry with this kind of treatment as a loyal customer who expects good service only to receive ****ty service like this