Car repo ambushed with no court order

On the 6th Sept Nedbank sent agents to collect my vehicle without serving me with a court order. I was demanded to handin the car and was made to sign a check list by their agent. One month later i get messages that the car is being auctioned on the 18th Oct. I have pleaded with the bank to give me an extension not to auction the car but their management denied my appeal. I would like to know whether is it legal for the bank to repo a car without a court order?