I once spent a fascinating amount of time calling a phone company. I was trying to pay a bill (not my own, but for a relative lest you thin I am some kind of strange phone bill fairy) and had managed to locate an old bill with the account number but I couldn't find a recent bill with a charge detail. I got to the total amount due, and while not mortgage payment territory, it was large enough that I just wanted to make sure nothing hinky was going on in the billing. I had to get transferred several times and explain my request before finally getting to a person who could provide the info. So, I can only imagine the frustration this French woman felt when she received the final bill for her service and discovered the termination fee was apparently ten trillion pounds. Or eleven quadrillion euros.
She called the phone company to let them know that clearly there was some sort of error, and the first few operators gave her the party line that the fees are automatically calculated, they have no control over that, and so on. Finally she managed to get to somebody who took a look and realized that the decimal point had shifted a tad too far to the right and instead of €11,721,000,000,000,000, it should actually be €117.21. Oops.