HI Vivek
Its been a nightmare for a lot of people. Apparently Shopify did a no index no follow and also blocked the [email removed] in robot.txt . The problem with that is if Google already indexed a lot of [email removed] pages, the no index will not work if there also a block Disallow [email removed] in the robot.txt Which means all of the indexed pages are stuck in google. Last update from a shopify staff is that there working on a fix to unblock it from the robot.txt . This way the no index will work and drop all of the [email removed] indexed pages. I know its confusing but you can get more info from this other thread.