Unfair treatment

Good morning, I bought a car and was financed by west bank,I got retrenched in February and informed the bank as I haven’t been able to pay 2 months of my installments. I have made payment arrangements that I will pay 2300 every until I get money to pay the arrears. I just sold a property and I’m waiting for the proceeds to pay the arrears, the has been a delay from SARS and I advised West Bank that I will only be able to pay the 2300 that we agreed upon. To my surprise I’m threatened as if I didn’t notify them and I didn’t pay the 2300 that I promised to pay. Can you please advise why am I treated like a dishonest person. Thank you