Oasis Bluetooth Smart Watch with Camera and Sim Card Support for All 3G and 4G Android/iOS Smartphones Black Smartwatch(Black Strap Medium)

Trouble shooting steps .Don't plug the charger in high voltage power sockets. Don't left charger on after removing watch from charging. Don't left charger on at night. It doesn't support 4G sim card,and also we have mentioned this in user manual. It has battery backup in standby mode but using all the features at a time will reduce battery backup. We always ship product but sometimes we send the packages by checking them initially. Due to overcharging battery always bulged out,ideal charging time is max 2 hours.