Both WhatsApp and Messenger are used on a mobile phone, WhatsApp is only available on a mobile smart phone, most mobiles use the internet at some point especially international calls. EE who are BT owned use hot spots on 3G instead of masts, the latest BT modems have a built in 3G transmitter receiver to increase coverage in dead spots, expect them to upgrade to 4G if they are not already there. When we were in the UK before the BT takeover we had a 3G aerial connected to our Plusnet modem and anyone walking past would be connected if the the 4G signal was lost. my PC is slightly to the right of Genghis
2012 HSE SD4 In Orkney Grey now gone, best car ever.