Hi @Kaylamaree, just to confirm are you having issues with your mobile phone coverage? If so, are the other people in your house also on Optus or with other providers?
Have you checked the Network Status page to see if there are any outages in your area may be affecting your service? Simply click on Mobile Outages and enter your full address into the search bar and if there are any outages, you will see them reported.
May I suggest having a look at My Optus Service Is Not Working: Troubleshooting Index for steps to help you get the best connectivity for your service. Just select service type you have.
If there are no outages in your area, you may need to perform a Network Reset on your phone. This will delete all saved network settings and WiFi passwords. This is to refresh all your Network settings on your phone without losing any data.
To do this, please follow the steps below:
iPhone - Tap Settings > General > Reset > Reset Network Settings
Android - Settings > General Management > Reset > Reset Network Settings
You can also try turning on Voice over 4G (VoLTE) and WiFI calling if you have a compatible device from Optus, this may help with any call issues. With these turned on, calls will be picked up through the internet to carry the call.
Please give the above a shot and let us know how you go.