iphone 6s has full signals but still cant make or receive any calls or messages. even my 4G is working but no phone calls please help

Hi Ayesha.khuram,

Welcome to the Apple Support Communities! I'm sorry to hear that you are having these issues with your iPhone; I know how frustrating that can be. If you continue to have issues making or receiving calls or messages, you may find the troubleshooting steps outlined in the following articles helpful:

If you can't make or receive calls on your iPhone - Apple Support

If you can't send or receive messages on your iPhone, iPad, or iPod touch - Apple Support

Regards