RBL Bank — Customer Care executive used abusive language

I have opened a savings bank account in RBL through online and they have sent their welcome kit to me through a courier company called Delhivery the courier executive called me and verified the address and they didn't delivered the package when I tracked with my AWB, I have found that it has returned to Coimbatore then I complained about this to RBL through my Twitter handle the next day one social media executive called and asked me about the issue and without any issue or provocation he started to abuse me in his language. When I complained about this they were just escaping from this issue asking to sent the voice clip again and again.