With whom Rajiv was talking? Guess
In the last Rajiv was talking secretly with someone on phone and talked about money to be given to that person.
My guess is Rajiv has hired a detective or some person who give all the information of what is happening back at home. Because we all knows how Rajiv loves his family. Being a older son of the house, he has always taken care of the family. He know under which circumstances he has to leaved the home and because of whom. He never trust shalaka. So he might be has a doubt that shalaka must do something which is harmful for the unity of the home. So to get in touch with the home indirectly, he hired as I say detective or some person and with that person he was talking on phone. might be possible that he don't want suman and adesh let know about it for some reason.