iPhone 7 Plus pairs to bluetooth headphones but not for phone calls

When the call comes in, are you answering it with the headphone, or on the phone itself? If you look at the phone screen, in the upper right of the group of selections, you should see Audio, and there you can select the headphones if you wish. Many headphones will not initially take the call if you answer the call on the phone itself. You have to transfer it. You can also check Settings>General>Accessibility, and see what the settings is for Call Audio Routing. It should be on Automatic, and the call should route to the headset if you have on connected. However, like I said, many require you to answer the call with a button on the headset rather than on the phone.

Lovemytech wrote:

I am answering and making calls with the blue tooth headset on.

Okay, thanks for that, but just to be sure, I understand that the headset it on, I'm assuming powered on, and on your head, but are you using the button on the headset to answer? If yes, and you aren't hearing, and I think I'm understanding that you are not able to use the button to change the audio when in the call, what happens if while you are in the call and you try to turn up the volume on the phone using the buttons on the side of the phone. What do you see on the screen, and does that change the sound any?

I notice in one of the screenshots that you have Assistive Touch on. If you tap on the Assistive Touch button, then go to Device, then look at the bell, do you see a line through it and the word Mute?

If that does not help, then I'm put of ideas, and I would say to try that trip to the Genius Bar that I recommended earlier.