Attero Recycling / Atterobay.com — Order ID - KK[protected] Payment on process since the last 4 months

I had sold my Iphone 5s, and they quoted me around 9400 Rs on the 7th of December. I am still waiting for the payment to happen. I had even requested to return my product which never happened. Now their toll free number is not available, they are not picking up their phone at their HO and they do not reply to mails. I heavily doubt whether the company has silently shut down with all the devices in their custody.