How do I know if a message about the PSTN or copper switch-off is genuine and not a scam?

Genuine providers will never ask for your bank details, an upfront payment, or remote access to your computer just to complete an upgrade. If you're ever unsure, hang up or ignore the message and contact your provider directly using the number on a recent bill, not a number given to you in the suspicious message. Be cautious of anyone claiming your phone service will be disconnected immediately unless you take urgent action.