How can I owe you?

In January 2014 I was retrenched. In April I downgraded my medical aid and in September had to give it up totally - not a good prospect.I hadn't really used it much so didn't worry. I then got a call from some punky little lawyer threatening to blacklist me. I explained the situation and I spoke to Discovery who said they would get i sorted. I have never actually seen an account for the so called outstanding amount - what it was for nothing. In 2014 I also took shortfall medical aid and am now being hounded for R600 for X rays despite the extra cover. I keep getting calls from this little punk and now that I have a job I need to rejoin Discovery but don't want to have to pay for something they said was sorted. let me make this clear. I did not abuse my cover. I pay cash for most of my medication because they wont put certain things on chronic and there was about R5000 in my medical savings. I didn't give up medical aid because I wanted to. I had no money. Starve or go to a state hospital. I think starving takes longer. If Discovery don't sort this out once and for all I shall be forced to find an alternative medical aid