Bad service

Standard bank financed my vehicle which I was grateful for. Then they requested proof of insurance covler which I emailed to them. I then received calls saying I owe them money. After countless calls I was told they took insurance on my behalf because they need proof of cover. I sent it and called to say I've sent it but still the calls never stopped. August they debited an extra R3000+ for insurance. I again called and emailed to have this rectified but have still not been assisted. I just don't understand how they can call me countless times to demand money I don't owe, then take my money and never want to return it.