Unauthorised debit order

Out of the blue discovery health decided to debit more than R5000 in my account Without my authorisation. I wanted to join their medical aid they let me down decided to cancel their Medical aid. Suddenly I see a debit order of more than R5000 Where else I was told because of my pre existing conditions I can’t benefit from certain benefits. For the past few no deductions Then today I see a debit order of more than R5000 . I am on I just return from isolation. They took money from my account after cancellation.