billed every month after cancelling. cant cancel

My name is nosisa ngcobo n i work at hullet tongaat and I have been a member of medsheild for the past 7/8 months. 3 months back i found out i was pregnant and some of the services i required were not paid by my medical aid so i decided to cancel. I have been to my HR dptmnt several times and they assured me they have cancelled bt after having the deduction on my medical aid for the second month i started calling medshield myself and still no luck. I sent emails however they say they deal with human resource department at work only. I had complications to my pregnancy and nw on maternity leave i cannot afford to lose R2800 on medical aid fees. so i called again today to cancel i spoke to a lady called mpho who gave me a name of someone at my HR who has to send some documents once again i went to work and no one seems to know this form. Im so frustrated and broke. I need this money and cannot afford cash bieng wasted because i will be paying cash for my delivery. Anyone who can help please help me so i know what to do. I do not need this stress and wil not be using this medical aid scheme in the future.