If you have another Telus phone, you can test your sim in it to determine if it's a network or device issue. If you have no issue on another phone, than the problem is with your device. If it still doesn't work with your sim in another phone, than it's probably network related. In that case, contact technical support at 1-866-558-2273 from another phone so they can troubleshoot while you're not on your cellphone. If you have a twitter account, you can also reach them @TELUSsupport.