Need Help- After Flash

So I have a SCL23 (G900J) model S5, and after flashing a newer more updated stock rom, my phone began having the following problems

• Can't connect to WiFi


• Can't connect to networks

• Related to this, I also can't use * # 9090 #


• And * # 9090# has no options for me to use

I just rooted the phone on the lollipop rom. Was hoping for a solution to this.
Also, * # 06 # shows me the MEID rather than IMEI

After reading some stuff on similar problems, downgrading won't help because I deleted particular software that allowed me to connect to networks in Australia
Please please someone help :)