Discovery Life deductions without approval

Policy Number ********** 488. I joined Discovery Life more than 5 years ago. My personal situation changed and I decided to reduce my life cover to the minimum level. On 17 Oct 2017 Discovery Life's COO quoted me on a reduced cover via email. I accepted the reduced cover on 17 October 2017. The amount deducted did not change. All attempts to rectify failed. On 13 February 2018 I informed Discovery Life by email that I want to cancel the life policy with immediate effect. Again nothing happened. I informed Discovery Life and my broker on 9 April 2018 with an urgent mail. To date I had no response. I expect a full refund including interest.