Block and Reverse Debit Order

Please block and reverse this debit order which has been debiting my account for the past 6 months. I was able to successfully reverse it for June and July but since then that option has disappeared. Please reverse and block for Aug 2020, Sep 2020, Oct 2020 and Nov 2020.

I wrote to my Private Banker but she hasn't got back to me since 24 October 2020.