Unauthorised debit amount

In October 2019, I was offered a Standard bank Mobile Sim card which I was much very happy to take up due to paying R39 for R107 airtime which has come in to be very handy for me. I was very happy with until this past Saturday where I checked my bank statement and I my account was debited to the amount of R461.43 now that has made me so angry and has messed up my monthly budget. So I called in and when I asked what was the reason that I have been debited so much to my surprise 3 months down the line I was told that the account that I have is a not limited package meaning its not a prepaid option so that came as a shock to me for I would have never taken it at all because I am not prepared to have such a contract and in the first place I took it because I was told that it was a top - up. So I was assisted by Andile Ref 304879 who is the one who told me something I was not told before. As a result I have cancelled it for I am not about to be getting surprises like this one because ever since I had it I knew that once my airtime was done, I would stop using for my data and airtime would be depleted. Now I really want this to be sorted and I want my refund back.