Am also having the same problem of hanging in this phone.it hhanged and I was unable to came out of the app or power off the.it stay hanged for an hour.then I rebooted the phone by pressing volume and power keys.now it’s working well.it’s been 1 month I bought this vivo y51l . The hung problem happened 2times till today. Other than that the mobile works well.but it’s not fit for JIO users