This is the first I heard of this, but apparently, a small manufacturing business had some $900,000 (thats right, almost 1 million dollars!!!) of toll fraud back in 2009. AT&T apparently sued the business when they would not pay the bill. AT&T recently dropped the suit, but the business owner is still maintaining his countersuit for legal fees he incurred in fighting the original suite.
Interesting of course because it is yet another toll fraud case. I would guess an attacker placed a dialer in the business to generate calls to toll numbers in Somolia. I can't imagine the attacker sold service and there were than many users who would make individual calls and/or that the business owner wouldn't have seen this over time.
Also interesting to watch the give and take between a service provider and business/enterprise, when this sort of attack occurs.