Bonitas not refunding medical aid savings

Termination of Bonitas medical aid is an absolute nightmare. I cancelled my membership in December and they delayed cancellation to end January. In February I was followed by another deduction as they claimed they had administration error and I had outstanding premiums. Tell me how do I have outstanding premiums when you submitting debit order request. Now I am being sent pillar to post when I want my medication savings refund. 5 months later I still have not received my refund and their call centre is useless.