Question about Netgear Nighthawk M6 Pro Mobile Router

Why doesn't this overpriced thing work? We've been travelling for a week now and so far the device has only worked once, otherwise it doesn't deliver internet to the mobiles. The device says 5G, full bars, is connected to the mobiles, but when we want to go online with the mobile, nothing works. How can that be? I thought it was a great and simple device, charge the battery, connect it to the mobile and off you go! But no, the cheese doesn't work at all.