My phone is HTC Desire SV, I tried many times to set the APN such as the guideline for Androi on the giff gaff instruction on this website. Turn on and off after setting again and again but nothing happen. I'm starting annoy with the internet service because I bought it nearly two weeks but don't know how can I use it. The guideline is clear but it didn't work. What I should do now?thank you for help!