Kotak Mahindra Bank — harassment to the core

Hi,
10 days before my due date i started receiving phone calls everyday stating ur due date is on 23rd, due to that inconvenience i stated i ll not make the payment i want to do settlement. But everyday atleast 20 to 30 times i receive call from the collections. Hence i requested to talk to a supervisor. A person named karthik spoke to me but the way he spoke to me was very insulting, he said i don't have the capacity to may after all 900. But i was ready to settle the complete amount at one shot which is 45000. But the way he spoke to me and his imsults are ridiculous which affected me mentally now am disturbed. I dont want to continue any services from kotak and am scared about the collection supervisor. Please help me from him.