IS THIS LEGAL

I received a call from a Lady from Finwell.She sounded very convincing about the product that she was marketing.She then put me thru to a Lady who did not explain anything over the phone but kept telling me to confirm on my cell some payment thing she was doing.I did not realize at that time that it was a debichek payment she was doing because she was rushing thru it.i was doubtful because it seemed to good to be true.i then contacted the lady who spoke to me initial to cancel the payment etc .she informed me that I must call the accounts dept which I did .I then emailed them a letter of cancellation immediately .the lady promised me that they will not debit my account.however R685 was debited last month and R5000 was debited yesterday from my account and another R75 was debited from my account yest.my question is that I did not sign or complete an application form or sign any forms for consent and how can they do this?is this legal?please refund my money asap .this needs to be taken up with NCR.