Flipkart — Worst service experience with Flipkart, Never exchange phone with them

Purchased this phone (Samsung Galaxy A51) and wanted to give my old Moto g4 for exchange as per their scheme. On the website, they offered me an exchange price of Rs. 1650. Be aware on the exchange price, they also charge pickup cost. For me, it was Rs. 100 additional. On the delivery of my new phone, the delivery body decided to reduce the exchange price of my old phone to Rs. 550 despite no technical issues. He also removed the screen protector on my old phone without my permission. I requested to speak to their manager regarding this. To my shock, The manager - Mr. Mayank argued that the delivery boy has the authority to do so was extremely rude on the phone and threatened me to block my account on flipkart. I refused to give my phone for exchange due to this. It seems like their exchange scheme is a rip off scheme. Very disappointed by Flipkart customer service.