******** debit from.a contract I canceled

In May.this year I joined the medical insurance with unlimited medical insurance and two weeks after that, I called them and indicated that I can not be able to continue with it because I'm no longer working. The lady that I spoke to said it was canceled and nothing was given to me in writing. Since May they have not debited my account and I was convinced that it was canceled. This Friday the 26th of June an amount of R1 153 was debited on my account, I then called and enquired as tonwhy was my money debited? They said I didn't cancel.my membership, I explained to them and they are refusing to refund me alleging that they don't have the date and the name of the person that helped me. Can I kindly be assisted with the above matter, as I'm not working and desperately need my money. Kind regards Molifi Moeletsi ***