Debited my account without my permision no signed

I contacted their call center inquiring about their student med-aid UKZN THE ONE FOR R350 I dont remember the name of a girl I spoke to but we agreed on opening the medical aid when she has sent me the documents to sign and proof that the person Im opening the medical aid for is a student, she took all my details including my account no. and my email address to send me the forms to apply and send back, but she never did the next thing month end of that month a debit order of R764 went off My account while we haven't signed or even have a membership no. with them and its a wrong amount that is being debited, I ve been trying to resolve this via their call center and they are giving me **** till now this has not been resolved and no one has contacted me ever since even when I ask them, I have spoken to more than 10 people in their call center they keep me on hold for sweet 30 minutes and hang up without helping me others promise to call me back they never do and Im calling them with my cellphone, Discovery has too much of ***** going on how do you debit someones account without them authorizing you, this is one pathetic and horrible service you can give you ripping people off their