I wouldn't beat yourself up over my suggestion...It's kinda a shot in the dark...I had an issue where I could barely hear other people...and was given the same advice...So it may or may not work...
I think I recall you having a Trailblazer SS?
I'll just put it out there, that my factory mic is nearly directly above my head in the head liner(03 Silverado SS)...I popped the mic/speaker out of the glue....pushed it over to the side a bit, and squeezed the Avic mic in it's place....It seems to do pretty good. People say that they can tell that I'm in my truck, but can hear me pretty good...better yet, there is no visible mic...