Fedhealth ***** premium's on cancelled membership!

I recently cancelled my membership of Fedhealth medical scheme due to them failing to pay a number of hospital claims. I submitted my cancellation letter with more than a months notice. My daughter is an adult dependent on me and her cancellation was separately stated in the very same cancellation letter with her full policy details too. Fedhealth cancelled our membership and ignored my daughters cancellation request and took off the next premium from MY account. I contacted them and was told to submit a separate cancellation letter which I did (and voiced my irritation that they neglected to ask me for this on my original cancellation letter). I have a string of communications for all of the above on record. I have followed up repeatedly to get the first wrongfully taken premium back and now Fedhealth have taken another premium off my account. This is blatantly ********* behaviour!