Stop deducting premiums as I have cancelled membership with you

I’m utterly shocked with the service rendered by this organisation. I have emailed them my cancellation of the insurance in October 2021 already and they have been deducting premiums despite this which I have been reversing with my bank . They sent numerous SMS which do not provide option for cancellation. I wish to reiterate that I’m covered now with another insurance . Can they stop deducting my money please .