I knew someone who was involved in the 1-900 business in the 90's. Apparently back then it was relatively common to DoS your competition by running up a lot of

I knew someone who was involved in the 1-900 business in the 90's. Apparently back then it was relatively common to DoS your competition by running up a lot of fraudulent calls to their numbers. The hope being that the telco would cut them off, and you'd have one less competitor. For my friend who was hit by this, it really sucked, because telco billing chargebacks in those days took 3 months or more, so it looked like he had hockey-stick month-over-month growth... until suddenly he didn't, because most of the "growth" was fraudulent charges intended to get him shut down.