Inside this article 3 sections
01 / Changing service
Locate the boundary
Does the fault affect voice, texts, data or one application? Does it follow the phone, one room or a particular time? Is the device using the intended SIM and is Wi-Fi masking the mobile result?
Check ordinary settings, allowance and any official incident notice. Restart once where appropriate. Avoid factory-resetting a device as the first response to an unexplained fault.
02 / Changing service
Compare one thing at a time
Try a second ordinary application, compare mobile data with Wi-Fi and repeat at another location if practical. Keep a note of each result. A working data connection with failed calls suggests a different investigation from complete loss of service.
Use only authorised devices and accounts for comparison. Do not delete an eSIM simply to mimic reseating a physical SIM. Changes that remove credentials can make recovery more difficult.
03 / Changing service
Give support a useful report
State the device model, relevant area, timing and affected service. Include the error wording and what you already tried. Ask for a case reference and the expected next action.
If an issue persists, use the formal complaint process. A sequence of clearly documented observations is easier to investigate than repeated vague reports.