Whoever runs that Wi-Fi network either shut it down or configured it so you can no longer see it/connect to it. If you don't wish to be on LTE all the time, I'd highly recommend you get your own Wi-Fi network/Internet connection (and properly secure it with WPA2). It's unwise to trust open/unsecured networks as those running them or others using the network may be able to snoop on you (see your personal information as it passes over the unsecured network).