Outsurance keeps debiting me even after iv cancelled numerous times

I had gotten a premium on my Jetta 4 last year 2021 December to pay R903 . They started taking money in February. In march I sold my car and asked that the premium be removed on that car cause I’d be getting another car . I went through all the docs to the agent who helped me join ,, my premium till to date hasn’t been cancelled . Iv been debited from march till June now … which is 4 months . I asked for a refund .. nothing has been done . My account has sometimes gone to a minus and those are charged iv had to pay .