That totally sucks.
Come to our call centre.
We're told to keep them on mute IF we want, but as long as we don't go over the limit for hold it's fine.
I haven't done the mute thing once, because I find it incredibly awkward when they start talking to someone there, and you're listening.
It's kinda creepy.
So yeah, I put everyone on hold all the time. I've never gotten any comments on it at all.

Also I never dispute QA because I hate the whole process. I got a zero for telling a customer that insurance will cover a damaged phone, when I should have said that the insurance will make that decision whether they want to cover it or not. Bullsh*t, but whatever. I'm too lazy to fight. Apathetic as hell.

So good luck fighting it. Hopefully you at least get it overturned.