My car repossessed over R40 000 yet I already paid R600 000

Good day, I hope this complain reaches the relevant person. I bought a car (Amarok) with standard bank in 2011 December. And the period of which the car was supposed to be paid up was 6 years and the 6th year was in 2017 December. There were times when business would be bad and i defaulted on some instalments but everytime i get back on my feet i would go inside the bank and pay. We always had communication with the bank regarding my failed debit orders. But sometime in 2018 i realised that the bank had stopped to debit my account and they stopped communicating, so my assumption was that my account was now paid up, plus it was now way over 6 years since our contract.

To my surprise when i went to apply for a loan at another bank where they told me i am in arrears with standard bank for the Amount of R40 000. I then called the bank to get clarity on that issue and i spoke to Dominique who promised to send me a statement of my account, which too him months before he could send it to me.

I planned to query some interests put on that account. Then after sometime after receiving the statement, i was approached by the agent to repossess the vehicle, i told them i was not even aware i owe the bank i only discovered recently. They advised me to make arrangements with the bank to pay the outstanding amount. I then called and spoke to Mandisa who told me there can't be any arrangements as they already issued the summons. I told her we never received the summons, she sent me the copy of those summons but they were not signed by anyone and never seen by anyone. We tried to involve debt counsellors but standard bank rejected that. So now they finally repossessed my car for a debt of R40 000 yet i paid over R600 000 already on that car. I went to the bank to plead with them but they are telling me i have 5 days to settle the amount remaining or they are selling my car.

I wouldn't pay R600 000 and refuse to pay R40 000 and risk losing my car. I am so frustrated I don't know who to speak to. I also need the bank to double check how they have been charging me because the statement show i was charged arrears interest even when the account was upto date.