Harassment by collection agency

Hi Sir, I have a Credit Card from RBL bank. I have been paying the bank regularly however this month I suspected some discrepancy and asked them for a detailed statement from the date of issuance of card. Basically I intended to pay off the entire thing after completing my Investigation. I didn't made any payment just because of the same reason. This weekend I was out of town, received a call in the afternoon from some bank executive who told me that he is at my place for payment. I Informed him that I am not in town and asked him why is he visiting my place without even Informing me. This somehow pissed him off and later he ended up abusing my entire clan and making death threats. I (Shocked about what happened) called the customer service team about it and Informed them about the same. They lodged a complaint and asked me to check back in two days. Yet again a received a call from the bank today with the same pattern. I am really scared now. I am going to pay off the entire damn thing but want to teach these scums a lesson too. Is there something i can do about it?