Very disappointed in Blackview device

Dissatisfied! Bought a BV6300 rugged phone for my husband. He works long hours in areas where he doesn't always have access to a charger. We reported to the support staff at Blackview that the device's battery doesn't last even a day. One of the screenshots i attached in my email to them shows that the device was fully charged 3 hours ago, had 8 minutes of screen time but the battery has 88% left. They said to send the phone to them, but did not say that we will have the cover the courier costs. They found nothing wrong with the device and we have to pay the courier. Very dissatisfied customer.