Most 'terrible signal' is one room, one wall or one switched-off setting. Work down the list; total cost: nothing.
iPhone: Settings → Mobile Data → Wi-Fi Calling. Android: Settings → Connections or Network (names vary). Calls then ride your broadband under your normal number — the permanent cure for dead rooms. No toggle? Your provider may need to enable it, or may not support it on your brand — check officially.
With 3G gone across the networks, calls need the 4G layer — and some phones shipped with it off.
Airplane mode on, count ten, off. Forces the phone to find the strongest local mast; cures a surprising share of "stuck on one bar".
Carrier-settings updates carry real network fixes, not just emoji.
Window beats inner wall; upstairs beats basement. Insulation and glazing are the culprits, not the network's grudge.
Postcode into the network's status page — planned mast work explains most sudden outages in seconds.
Ring or WhatsApp and ask your question out loud — coverage, switching, a deal you're not sure about, a bill that stalled, a call that smelt fishy. We'll talk it through in plain English.
Calls: standard landline rate (020), usually inside your inclusive minutes. WhatsApp: free on your data. We give general guidance only — we can't open or touch any network account, and we NEVER ask for passwords, one-time codes, banking or card details.