Can we please see some actual numbers! Given the advertiser's "popularity" it's possible they were over-charged something like $4 for a few hundred clicks in which case it's certainly not an enormous mistake.
It also earns a tonne of revenue through fraudulent clicks many by competitors. It's a big deal and Facebook needs to make attempts to fix it but the problem will never be completely solvable.
(And yes, the Wahanegi was much more interesting, which I guess was why the number stuck in my head)