Coincidence

Recently switched my UK Sim to a French Sim in my nexus 4 whereupon it didn't recognise the Sim. Have checked and it's the phone not the Sim that's the problem. A week later my nexus 5 can't get mobile data and a day later can't get any phone reception even though it has been set up for roaming and was working fine till then. Otherwise ok eg WiFi.
Coincidence or something else?