If you are using whats app to make phone calls DO NOT join Tesco Mobile as you cannot use Tesco Mobile data when making/receiving calls. Tesco Mobile acknowledges this issue, but unable to say it will be resolved (if it will be rectified at all) and it has been ongoing for approximately 4 weeks.They kept telling me that "whats app" is a third party app, and there is nothing else they can do to help. Interestingly when I use vodafone or EE sim cards, I have no issue with making call via whats app. I am honestly shocked with how poor the customer service is at this company! I have been with Tesco Mobile nearly 10 years now, and everytime there has been an issue their customer service has been really poor. However how they handled the whats app issue has been appalling. Due to whats app issue I have attempted to leave Tesco Mobile but they have told me I would have to pay £240 for leaving before my current contract runs out. My curent contract runs out in December 2020 (I have four contracts), I will be moving to a more reputable service provider.