IP address suddenly changed from 192... to 144... and now it can’t connect via Ethernet. Pls help

I’m in Australia and we just got fiber/nbn it was working for one day and now the IPv4 Address suddenly changed to 144... same with the gateway but when it put in that gateway into chrome it doesn’t take you to the router. Even if you put the original 192... gateway it doesn’t work. Any help would be appreciated