Fnb Cheque and debit card disputes

Fnb will not protect your money as a client. I recently logged a complaint to Fnb about a doggy merchant who debited my account after receiving a faulty rental car which also got into an accident. Two amounts were taken from my account Fnb only refunded one and requested that I resubmit for the second amount. I changed cards because of this merchant to my surprise they are still debiting my acc. Question will be how is that possible since they do not have my new card details. For soo many years banking with FNB I’m highly disappointed and don’t feel like my money or anyone else’s is safe