NO RESPONSE!!!!!

I have sent a number of e-mails to the medical scheme regarding shortfall on fees. This has been happening since August 2015. To date, I have had no response from the medical aid, no call center agent has made contact with me. I am now at a point where I am not willing to pay any further bills as all my premiums are paid in full. I would like a response back immediately with regards to this matter as this is now becoming tiresome to run after the medical aid and get no joy out of it!