*****ing money after membership was canceled

I cancelled my membership on 22 Aug 2022, requesting the cancelation to be effective from midnight 31 Aug. I received an email confirming my membership cancelation upon which I app**** to my new medical aid, effective from 1 Sept 2022. On 1 Sept Bonitas deducted my premium. I contacted them to find out why, as my membership is canceled. The Bonitas employee informed me it is a mistake on their side and she will log a refund (which I receive an email for informing me the refunf will take around 7 working days). After not receiving any refund nor feedback for 3 weeks, I contacted Bonitas again. This time the Bonitas employee informed me that cancelation period is 30 days. When I informed her that this was never communicated to me and that I now had to pay 2 medical aids in one month, she said I must ask my new medical aid for a refund for September. I told her that I don't see why I must sort out the problem as this is not something I caused. I also asked why I wasn't told this when i phoned on 1 September. I then asked to speak to a manager, I was put on hold for around 5 to 10 minutes, after which she returned to the phone and told me the manager will give me a call back. I then asked her for her name, but she just dropped the call, and to no surprise no manager ever phoned me back. Not the service I ever expected from Bonitas.