In Croatia, where more than 30,000 refugees and migrants have crossed into since Hungary closed its borders last week, one tech start-up is helping them get Wi-Fi access by carrying hotspots on their backs. "3G network is working ok when we arrived, the rate was even a little over 5 Mbps but was soon stopped working," the company called Otvorena mreA3 4a, or "Open Net," wrote on its Facebook page, adding that the network connection is constantly dropping out.