I was in Tenerife for 7 days recently.  For the first time I was able to use my phone to make and receive calls back to Ireland.  However, will I could not call from What's App or send/receive messages via hotel Wi-Fi.  In other words, I had on internet on my phone in hotel or moving around and unable to use google maps.  Then on return to Dublin, problem changing back phone to home.  No other network gives these problems.  Any help would be appreciated.