IPhone 4 Can't make calls but is still connected to company. (Rogers)?

.Hello, I just got an iPhone 4 and it will not connect to my phone company. I've already called them to activate the sim card but no matter what it will not let me make calls. I have bars and it's even connected to my phone company (Rogers) but it still won't let me make calls. I called the company back and they just keep telling me to restore the iPhone and it should work find but nothing is helping.

Go to best buy and see if they could help also contact apple company, check your warranty to see if you can send it back to apple inc. Also the problem might be your service provider and not the phone