A coverage checker is an estimate, not a guarantee that every room, handset and moment will have signal. But that does not make every coverage complaint invalid.
Identify the failure pattern
Record whether the problem affects calls, SMS, mobile data or all three; whether it is indoor, outdoor or both; whether it is one postcode or multiple locations; and whether it began after a network/device/SIM change.
Key points
- Coverage-map prediction.
- Actual signal at the locations that matter.
- Device and SIM behaviour.
- Known network fault or maintenance.
- What the salesperson represented before the contract.
Coverage maps are predictions
Provider and Ofcom coverage checkers are useful evidence but cannot capture every building material, local obstruction or temporary network condition. If a salesperson made a stronger specific promise, for example that indoor coverage at your address had been checked and would work: preserve that representation.
Rule out device and SIM problems
Test another compatible handset or SIM if practical, restart/network-reset as appropriate and check whether multiple customers on the same network are affected. Providers have been banned from selling locked handsets since December 2021, so modern provider-sold devices should not normally create a network-lock barrier when switching.
Persistent local network problems
If the provider accepts a mast/network fault, keep the incident reference and estimated restoration date. Repeated closure/reopening of tickets can hide the duration, so maintain your own chronology.
If the service is materially unusable in the key location and was sold on a specific representation, consider whether the sales evidence, contract and complaint remedy support release or another solution.
Roaming and Wi-Fi calling are separate
Do not let a provider answer a domestic coverage complaint solely with roaming or Wi-Fi calling unless that is a workable contractual solution for you. Wi-Fi calling can mitigate indoor coverage but relies on another connection and compatible equipment.
Coverage maps are useful evidence, but they are predictions
Ofcom's Map Your Mobile checker combines network-operator coverage predictions with performance information. The coverage model cannot guarantee a signal at every exact point: buildings, trees, terrain, congestion, interference and the handset itself can change real-world results. Save the result you relied on at the time of purchase if coverage was important to your decision.
A provider should not simply point to a map and treat it as conclusive proof that your service works. Equally, a poor result in one indoor room does not by itself prove a network-wide fault.
Keep a location-and-time log
Record where the failure happens, whether you are indoors or outdoors, the date/time, whether calls, texts and data are affected and whether other users on the same network see the same problem. A pattern confined to one building may suggest indoor propagation; a sudden problem across a wider local area may suggest an outage or network change.
Separate a persistent coverage problem from a temporary fault
Check the provider's service-status information and report a fault where appropriate. If the problem began after previously reliable service, ask whether a mast outage, maintenance or network change is recorded. If it has existed from day one, focus more closely on what coverage was represented before the contract and whether the provider had any specific coverage commitment or trial/cancellation arrangement.
Run basic device checks without letting them consume the complaint
Try another location, restart the phone, confirm network settings and, where practical: test the SIM in another compatible device or another SIM in your device. Record the result. If the provider repeatedly asks for the same troubleshooting after the fault has already been isolated to its network, refer it back to the recorded tests and ask for the next diagnostic step.
If the service remains unusable
Ask what remedy the provider offers under the contract: network investigation, replacement SIM, account credit, migration to another tariff or release from the minimum term. The correct outcome depends on the cause, the sales representations and the provider's terms; there is not a universal rule that every patchy-signal complaint automatically cancels a mobile contract.
Evidence worth keeping
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Related telecom guidance
Official sources
Check the rules behind this guide
These are official or primary sources for this topic. Rules, scheme terms and deadlines can change, so check the live source before relying on a formal time limit or procedure.