Airtel — call center etiquette

I recently received a call from your calls center proposing a plan. On reverting that i was really busy and not interested since i am not a consumer of the telecom service, the caller was really rude. He hung up the call without waiting for a reply. As a previous consumer of airtel, this call has reminded me about why i even changed the service in the first place. [protected] was the number through which i received the call.