Appreciate your help!
I have spoken to optus agent through LIVE CHAT they tried everything, network reset, re triggering, etc. Also, i have changed my sim card twice with same number. Whenever i go optus store the phone works well because they might be having good network and boosters in store. So they are not paying much attention. I m soo stuck ;(
Are you just having trouble in the one location i.e. at home?
Did the person you chatted to check if the coverage at the address, check if there are any network outages?