Firstly, check whether your device(s) are 4G compatible, and if you're able to use 4G Calling. If you're a Mobile Broadband customer, please also check whether you have a 4G device. You can do this in our Device Support hub. If you’ve recently upgraded your handset or device, you may not need to do anything.
If you do have a compatible device(s) with 4G data / 4G Calling, simply double check you’re connecting to 4G via your device settings, using the Device Support hub if you need help on how to do this.