Incorrect debit order amount

I have a complaint regarding a monthly debit order which should have subsequently been reduced following my Mother's claim on 17th December 2020. This is on a funeral plan insurance policy number ***, where I have been paying R143.40 which covered both myself and my late Mother.

I realized that in January 2021 they still debited the same amount even though I am now the only person covered on the policy. Immediately I sent an email to Liberty notifying them and requested that they rectify their error. They never bothered, come February and March 2021 they still debited the same amount. And I have sent numerous emails to them, last one I sent in March 2021 after discovering the same error re-occured.

I need this rectified the soonest, and Liberty must refund me accordingly.