The original sums didn't exist, they were computer generated errors.
But otherwise, I think I was asking the same thing. Once they knew that the Horizon system was generating these errors and innocent people were being forced to pay up, then to me it would appear that they were doing something criminal, they were extorting money.
I also wonder about the people who paid over sums of money but weren't prosecuted, and coerced into paying. Are they going to get compensation. They are still victims.