Unsuccessful cancellation a huge discomfort

We were Medshield customers but were excluded for my husbands back injury, resulting in having to get help from state funded institutes. August those institutes found out we have medical aid and refused to help us further. Medical aid declined all applications for chronic meds, now we have to pay it cash. Medshield has increased their contributions and is limiting us to certain Dr's and hospitals. We have since tried to cancel the medical aid but just nobody is responding to our emails. They just continue to try and deduct their premiums. But since we have to pay cash we are not financially able to continue with paying for own meds and the increased medical contributions. How on earth do I get those people's attention to get this cancelled.