One way is to show up in person and ask. It's a lot easier to negotiate face to face than over the phone. It's the same when negotiating a price for a car, a hotel, stay, etc. I answered your other question elsewhere in this topic.
If the bill is potentially one of those crippling high ones, I'd suggest it's worthwhile to invest the time doing this, despite it being maddening.
If the bill is potentially one of those crippling high ones, I'd suggest it's worthwhile to invest the time doing this, despite it being maddening.