Dissatisfied with Nedgroup Funeral policy

I am really annoyed with Nedgroup Insurance's service. I took out a funeral policy for my mom with them in April2018, they started their deduction in May 2018. It went well up until November 2018 that's when I notice that they didn't deduct for November. I phoned them to ask why they didn't deduct they said it's my account but they will deduct in December. Come December still they did not deduct, I called them again but they said that the debit order was rejected. I told them there is no way it could be rejected as I still got my money in my account. They asked me to send them my bank statement so they could see, and I did send them that and a lady called Laurelle Latchment promised to investigate and get back to me. I had to follow up with her with no response from her side. Until she told me that the IT department said there is a problem with my bank and I should go ask them. I went to my bank and they said Nedbank didn't even attempt to deduct onto my account. When I gave Laurelle the feedback from the bank she asked me to do a manual payment so that my policy does not lapse while they still investigating. I have been sending her emails for feedback with no response from her side till to this day. I call their call center but they always hang up the phone. I want to cancel this and get all my premiums back as it clearly was not my fault. Who do I speak to if every agent hungs up the call on ear after hearing my story?