Why after unlocking ZTE F327s AUSTRALIA I DON'T HAVE ANY SIGNAL ?

The reason is this phone is 3G only phone (NO 2G) and with only one frequency 850MHz (Telstra) compatible. In Australia, only Telstra use 3G 850MHz and so the phone will work with Telstra and its dealers' sim only regardless it's unlocked or not. Lycamobile is a Telstra dealer.