iPhone 6 will not dial some numbers correctly

Hello Gurugary812,
From what I understand, you are having issues with making phone calls and the people you are calling can't hear you. I know that situation can be frustrating, but let's see if we can get to the bottom of it.
What you will want to check is the microphone. Take a look at the troubleshooting below for some troubleshooting ideas. One thing to consider is making a voice memo to see if your iPhone picks up your voice. If after everything and it still does not work, then you will want to contact Apple Support for further assistance.
If your voice is too faint or sounds unclear using iPhone, or iPod touch
https://support.apple.com/en-us/HT203792

Fix common issues

Follow these steps, testing after each with Voice Memos.

1. Unplug anything plugged into the headset jack.
2. If you're on a call and holding your phone next to your ear, speak into the microphone and make sure you don't block it with your fingers or shoulder.
3. If you're using a screen protector or case that covers the microphone, remove it. Clear any debris from the microphones.
4. Restart your device.
5. Update to the latest version of iOS.

If you've tried these steps and people still can't hear you well on calls, contact Apple Support.

Take it easy