Find the boundary of a mobile fault

Check whether the problem affects calling, ordinary texts, all data or one app. Note whether it follows a location, device or time. Confirm the selected data SIM and whether Wi-Fi is concealing the result.

Review basic settings, allowance and any official incident report. A single restart can be reasonable; a factory reset is not a good default response to an unexplained network issue.

Try a different ordinary app, another location or Wi-Fi versus mobile data. Change one factor at a time and keep a note of the outcome. A phone with working data but failed calls needs a different investigation from one with no service.

Use only devices and accounts you are authorised to access. Avoid deleting an eSIM simply to imitate moving a physical card. Preserve working routes for account recovery.

Provide the device model, relevant area, times, affected service and error wording. Explain which checks you already completed and ask for the next action and reference number.

Repeated problems may need the provider’s formal complaint process. Keep a clear chronology instead of a large set of unlabelled screenshots containing personal information.