Cancelled Medical still deducting monthly premiums

On October 5th 2015 I cancelled my Discovery Medical Aid telephonically with their call centre on which I was informed that my last deduction was 1 October as I cancelled so early in the month,on the 1st November 2015 a deduction of the amount of R1895 from discovery was made out of my bank account of which I enquired after 3 phonecalls to their call centre they could not pickup that they deducted this but confirmed it was inactive and should not have deducted,due to my busy schedule I forgot to follow up on this and now 3 December 2015 Discovery Medical deducted R2117 from my bank account what feedback am I gonna get this time however if u just skip one month of payment they quick and ready to suspend your medical. This is totally unacceptable for such an organization and then they can't tell U why it was deducted. May I add that this happened despite the fact that I have put a stop order on my debit order,so how they still deducting I would love to know.