It's malicious. Some of us reps try to help you out and get it all reversed. Others don't give a shit at all.
The main thing you can consider is not paying, blasting them on social media, or just keep calling until you get a nice rep who will fix it, hopefully permanently.
Our system deliberately renews/adjusts prices per gallon and service contracts to pretty much whatever price the company feels like extorting. I've seen customers charged $4000 instead of $2000 countless times. Some even pay it.