Q: iPhone 6plus cannot make outgoing calls

I haven't been able to make outgoing calls and outgoing messages through my iPhone6+ since yesterday. I have done research and have tried suggestions like turning the phone into airplane mode, turning off the iPhone, re-setting the network settings, erased all the content of my iPhone and restored backup, erased all contents and used as new phone but I still cannot make outgoing calls nor can I send test messages. At first I thought I did not have sufficient money on my sim card however when I tried my simcard on another iPhone, it worked perfectly. I also tried another simcard on my iPhone, but it still can't make a call. I have never had this problem since I got my new iPhone6+ last December. This is the first time I've had a problem like this with an iPhone and I've been using the iPhone since iPhone 4s,iPhone 5 and iPhone 5S. Could there be something wrong with the unit that I have? Is there any other troubleshooting I could do?