Dishonest Bolt driver

My kids were ****** change by the driver named Njabulo who took my kids this morning, he took more cash from my kids than what was due to him. The trip was only R36 but he took R105 cash. I only found out when they came back. I've sent an email to support @bolt but there are no options for my query from their app. Please help me get my change back from that dishonest driver.