Threats from standard bank agents

Earlier this year I went to standard bank to alert them that my December 2018 installment was not debited and soon after that I started receiving phone calls from different agents claiming to be sent by the bank to recover their money or take my car. I tried making arrangements with these agents numerous times but nothing fell into place. Recently another one called and I asked to meet with him he told me there is no need to meet I must just send my documents and to him. I called the bank they transferred me to their cafeteria. An hour ago I got a call from a company called Ashtons by a man named Anton who is threatening me that if I don't pay R5k now they are coming to fetch my car. I have been trying to get assistance from the bank directly so that I can make installment arrangements. Please help because at this point my personal details are laying around in companies that won't even give me their own details to verify whether it's true or not they were sent by standard bank. These are rude people who force us to commit because we are in trouble with payments. I was honest from the start I went to the bank not the other way around.