Discovery activated medical aid while I am still on Gems and I am paying for both medical aids schemes

I am so numb as I am typing this. I recently joined discovery in June. The lady I spoke with told me to give her my employee number as she said she would do everything on her side. She asked for my account number and specifically told her that this account number should not be used to deduct from my account as all deductions should go via my payslip. If they really record those calls they will note that I said this twice and the lady said it’s standard procedure that she takes the account number from me, but no deductions will be performed. When I received my payslip I was surprised that GEMS deducted from my payslip and not Discovery when I made a follow up Bruce from Discovery indicated that there will be a deduction from my private account on 01 July 2024. I called Discovery again and the person I spoke to said I should terminate my Gems medical aid first so that I can send Discovery membership certificate that will show them that the medical aid has been cancelled

This means I have paid GEMS medical aid and Discovery at the same month which has inconvenienced me to a point that I am not able to buy groceries or pay my son’s school fees this month

How can Discovery activate a medical aid while I am still on another medical aid. Whats even worse is that they have deducted before I even finished a month with them as I was still trying to sort out the mess they have put me in I am frustrated and do not know what to do