Trouble transferring from Company to Private

I have been on Discovery medical aid for over a decade now. I am currently on a plan through my employer (employer chose plan for all employees), and I am leaving the company. I want to upgrade my medical plan as I now have a choice of plan. I haven't used any medical this year yet. Discovery will only allow me to DOWNgrade my plan, despite the fact that I am moving to a private client and want to pay them more money each month. They said I should have told them last year, however last year I didn't know I wasn't going to be with my company beyond January. After an hour on the phone I am still getting a standard NO from everyone. In a time when there is so much competition in the medical aid space, and there are some good alternatives, you would think that your rules would be more tailored to suit different situations. I'm not a regular client trying to upgrade for no reason.