On the one hand I’m sceptical that a company couldn’t tell customers ahead of time what fees they might be paying.
On the other hand, I once worked for an ISP that deleted its customer database and all backups to save itself data warehousing fees and literally had no idea how much customers were paying or what services it was providing them. So it does happen.
On the other other hand (yes, I have three), incompetence shouldn’t shield you from the consequences of failing your responsibilities.