I feel like nobody is actually reading what I am writing. This is not a problem with an app. This is a problem with the phone service. I am not using an app, just placing a call.
I am sorry that I didn't completely understand. I did some research on this issue and now I completely understand how you did the conference call. I found that some callers used a bluetooth headset and it made the volume higher. Does this happen on all calls or just conference calls? This may or may not be an answer but I am still doing research. I just wanted to let you know what I found so far. I will let you know what I find later.