Membership canceled

Let's start from the beginning. I joined discovery medical scheme in 2010. Been on the keycare plus till 2016 when I resigned at the company I worked at. Few months later i joined discovery again but joined a more expensive plan as the new company contribute 50% of the cost. In December 2016 I went to the doctor for severe back pain and was referred to a specialist. Went for a Ct scan and MRI scan which the medical aid did not cover. Went for 2 injections into my spine under the Ct scan which also cost me a arm and a leg as the medical aid did not cover it. So i need to go back for another 6 injections and the specialist requested authorisation from the medical aid and it gets declined and nobody can tell me why. After several phone calls and months passing by discovery tells me they did send a form to the doctor to get completed but did not get it back. Took them more then 3 months to finally followed up on the form. Discovery informs me that they did receive the form and that they will review it and get back to me. Again took them a few weeks to review and call me back to inform me that my membership has been cancelled as I did not enclosed my back problem when I app**** for medical aid. Now my thing is my work requires me to do heavy lifting and it's a norm that I stressed my back a little to much at days and I did go to the doctor for pain ****ers or a injection. In plain simple words it seems discobery are saying I joined the medical aid cause I knew I got a back problem If I was at the doctor every month for my back i would say I got a back problem but that's not the case. Not sure what to do or who to contact cause to me discovery seems 1 sided. 7 years at discovery and that's the service I received. YOUR MEMBERSHIP HAS BEEN CANCELLED