Ty Denny Crane! My problem was that I was scared to turn on mobile data, because they always warn u about big additional charges. Once I turned it on, the voice calls went through. I hope they won't charge me over and above $15 that I paid for add-on...
Ty DennyCrane, actually my problem was that I didn't turn on mobile data because they always warn u about the charges. Once I got over my fobias and turned ot on, it was ok. Ty 4 taking your time to answer to my request.