Double debit

During my resignation month at my previous employer , I completed a medical aid transfer form to ‘private’. A while after that I completed forms to transfer from ‘private’ to my new employer. DISCOVERY got the admin process mixed up which resulted in my bank account being debited , as well as the contribution being deducted from my salary. The medical aid deducted from my bank account has resulted in my debit orders being unsuccessful as provision was not made for this debit order which should not have happened, and my bank charges R150 for a failed debit order. It is 15 days later and the issue is not resolved ! No apology, no refund and no pay back on the bank charges as well as SUCH a never minded attitude! What must I do to get MY money back from you ?