Harassments From The Bank

I am using this platform as my last resort and hoping that STD Bank will just leave me alone. I received countless calls from their consultants that i owe them over R 400.00 in car insurance because i did not submit my proof of insurance in 2017 when they financed my car. Have been paying the Instalment with the bank agreed without fail even during this trying times. I have also been paying insurance ever since and according to STD they think i might have cancelled the insurance, but i am telling them it is not cancelled and they need proof. How is that my problem? If they need this information, they can access their Archives and get the information and call my Insurance to confirm whatever they want to confirm. I am now physically not well about this whole thing as every cent counts. I was clear to them that i do not authorize then to increase my instalment and i don't think they have the right to do that. I really hope the call i received today was the last one. Can i ask STB Bank nicely, if they feel there is information i did not submit in 2017 and i was informed about, to send that communication, then we can talk. Other than that, please leave me in peace