Cancellation of medical benefits contrary to instructions - Breach of contract - Urgent

In the middle of November I sent my termination letter to Bonitas to terminate my medical benefits from 31 December 2018. Thus the last day I would be registered on the fund would be the 31st of Dec. Bonitas requires a 30 day notice period to terminate your existing contract with them. On 1 December 2018 I received an email to say that my contract has been terminated. on 30 November 2018. This clearly being contrary to my instructions. To top this matter further I then received a sms from the bank confirming that my December premium was taken by Bonitas. So they cancel my medical aid contrary to my instruction and they take my money. I will most likely struggle to get the money back. In an email following up on the receipt of the termination letter I specifically asked whether I need to cancel the debit order or not. I did not receive any response to my querie. I have also requested to immediately be reinstated for December 2018. My email dated 1 December 2018 also advised that I will hold Bonitas liable for any medical costs that I may incur if something happens to me due to their negligence of ending my benefits contrary to my instructions. My benefits were terminated prior to the lapsing of the 30 days that Bonitas requires. Clearly there is a breach of contract.