Discovery robbing people of their hard earned money.

I was a member for the past ten months and have been paying 2700 for the first few months and changed to the other plan for 2200 and when I had no savings there was no back up plan ,never been admitted to a hospital. I decided to change to a medical aid that offered better services and when my company sent them a letter of cancelation they say I owe them because for some reason they say I spent more than my savings and the last time I checked I had 62 rand left and haven't used my medical savings in a while and how this possible because it does say that funds are depleted if that is the case and what happens to my monthly contributions since I never used any hospital plans or anything besides the savings. This is day light *******.