Okay so i was having the exact same issue with my Bold 9700 and tried calling AT&T a few days ago but they were zero help. The "customer service" rep actually told me that she has the same phone and has never had that issue so she's not sure why I'm having it. Needless to say I was enraged and told her that I didn't have the issue up until a week ago but I do now and it is inevitable that it happens to her as well.
Originally Posted by johnny4lsu
Anyhow, I was able to get the volume issue fixed at a local shady, albeit helpful cell phone store near my work. It is one of those independent cell phone stores that do repairs also, and the guy was able to open up the casing on my phone and somehow fix the issue.
My volume works fine again now, so I suggest you look for a local cell phone repair shop because that's the only thing that seemed to fix my issue.