Paytm Mall - Issue regarding exchange of old phone with that of new one and the exchange cash back that to be rec

I purchased a mobile from paytm which was tagged with an exchange offer that is we can buy a new phone by exchanging our old phone so I thought to buy a new phone by utilizing the exchange offer which was offered by the paytm company. My old is HTC desire *** ultra edition and its exchange cash back was priced at Rs ****. Everything went good until the date of pick up of my old phone for the exchange cash back but after that it was very horrible and frustrated thing to me as the pick up agent cancelled the pick up of the old phone under very unreasonable terms and without my consent and now I'm facing a lot of difficulty in rescheduling the same.
Here I want to sue the Paytm company, shadowfax company and the pick up agent who is the initial and sole person because of whom this all happened.