In the case of my company specifically, I'm tempted to say the system is working as intended. A lot of the workflows are deliberately complex and obfuscated, though, so users are trying to enter $2000 but the system will always generate $4000 unless you know exactly which buttons to press.
Who's to blame for this? The CEO and CTO I would say. They want to generate as many inflated bills as possible and then make it really hard for the customer service rep to submit an approval for it to be adjusted.
They train the reps to say, "sorry sir, this is what my computer is telling me your balance is."
The customer then either pays or leaves the company, at which point they are charged an early terminaton fee and threatened with small claims court.
So yeah, I really feel this corporation directly desires a complex and costly process since it has a near monopoly on the market and the cheaper competitors are plagued with product quality issues as opposed to service/billing issues.